#!/usr/bin/env python

##Purpose of this calculator is to make solving and checking more
##simple and accurate.

##The TKinter is here to show us a calculator that can be used when
##your calculator has a problem or is missing or lost.

##The trail in the back of the calculator has all the previous
##operations the user has done, showing off all of the values and
##steps.

##Here is the order of operations from strongest (top) to weakest (bottom):
##    nCr, nPr
##    x^y, root
##    *, /
##    +, -, mod, and, or, xor, lsh, rsh

##Note that this program /should/ work against a DOS window!

##Created by Nicholas McConnell in 2010

from random import * # To work the [Rand] button, we need to import this.
from math import * # This has most of the scientific operations.
from Tkinter import * # By using this it is possible to layout in Tkinter

root = Tk()
root.title('Calculator With Trail')

txtContents = StringVar()

intInv = IntVar()
intInv.set(0)
intHyp = IntVar()
intHyp.set(0)

parCapt = StringVar()
parCapt.set('')
memCapt = StringVar()
memCapt.set('')

operation = []
for i in xrange(26): # 0-25 levels of parentheses
    operation.append([])

# This gets us [[], [], [], [], [], [], [], [], [], [], [], [], [], [], [], [], [], [], [], [], [], [], [], [], [], []]

def stringOut(ls):
    """Return the same list with all empty strings removed."""
    return [x for x in ls if x]

par = 0 # Number of open parenthesis levels
memory = 0 # Number stored in memory
stiffen = 1 # Does the calculator want to clear the current number when a new one is entered?

##The following functions are defined because they are not yet attributes made in the math module here in Python 2-5-1.
##They have underscores because them without underscores will be read against Python 2-6-1.
##For example, atanh(0.1) would be evaluated here as <builtin-function log>.

def __asinh__(x):
    # Area hyperbolic sine of x.
    x = float(x)
    return log(x+sqrt(x*x+1))

def __acosh__(x):
    # Area hyperbolic cosine of x.
    x = float(x)
    return log(x+sqrt(x*x-1))

def __atanh__(x):
    # Area hyperbolic tangent of x.
    x = float(x)
    return log((1+x)/(1-x))/2

def Fact(x):
    # Return x!.
    # nCr = (n!)/(r!*(n-r)!), nPr = (n!)/((n-r)!)
    assert x >= 0
    assert isinstance(x, int)
    f = 1
    for i in xrange(1, x + 1):
        f *= i
    return f

def actRand():
    # Input any random decimal (to 16 places) greater than or equal to 0 and less than 1.
    global txtContents, operation, stiffen, intInv, intHyp, angGroup, __asinh__, __acosh__, __atanh__, parCapt, memCapt, par, memory, Fact
    R = randrange(0, 10000000000000000L)/(1.0e+16)
    txtContents.set(str(R))
    print '           rand %s' % R
    stiffen = 1

def actPi():
    # Input value of pi.
    global txtContents, operation, stiffen, intInv, intHyp, angGroup, __asinh__, __acosh__, __atanh__, parCapt, memCapt, par, memory, Fact
    txtContents.set(str(pi))
    print '             pi %s' % pi
    stiffen = 1

def actFact():
    # Input factorial of displayed number.
    global txtContents, operation, stiffen, intInv, intHyp, angGroup, __asinh__, __acosh__, __atanh__, parCapt, memCapt, par, memory, Fact
    if stiffen == 0:
        print '                %s' % txtContents.get()
    if float(eval(txtContents.get())) >= 0.0:
        txtContents.set(str(float(Fact(int(eval(txtContents.get()))))))
        print '             x! %s' % txtContents.get()
    else:
        print '        (Negative arg in x!)'
    stiffen = 1

def actComb():
    # Enter nCr into function.
    global txtContents, operation, stiffen, intInv, intHyp, angGroup, __asinh__, __acosh__, __atanh__, parCapt, memCapt, par, memory, Fact
    if stiffen == 0:
        print '                %s' % txtContents.get()
    print '               nCr'
    operation[par].append(txtContents.get())
    operation[par].append('nCr')
    stiffen = 1

def actPerm():
    # Enter nPr into function.
    global txtContents, operation, stiffen, intInv, intHyp, angGroup, __asinh__, __acosh__, __atanh__, parCapt, memCapt, par, memory, Fact
    if stiffen == 0:
        print '                %s' % txtContents.get()
    print '               nPr'
    operation[par].append(txtContents.get())
    operation[par].append('nPr')
    stiffen = 1

def actRec():
    # Input reciprocal of displayed number.
    global txtContents, operation, stiffen, intInv, intHyp, angGroup, __asinh__, __acosh__, __atanh__, parCapt, memCapt, par, memory, Fact
    if stiffen == 0:
        print '                %s' % txtContents.get()
    if float(eval(txtContents.get())) != 0.0:
        txtContents.set(str(1.0/float(eval(txtContents.get()))))
        print '            1/x %s' % txtContents.get()
    else:
        print '        (Division By Zero in 1/x)'
    stiffen = 1

def actSqr():
    # If Inv is checked, input square root of displayed number.
    # Otherwise, input square of displayed number.
    global txtContents, operation, stiffen, intInv, intHyp, angGroup, __asinh__, __acosh__, __atanh__, parCapt, memCapt, par, memory, Fact
    if stiffen == 0:
        print '                %s' % txtContents.get()
    if intInv.get():
        if float(eval(txtContents.get())) >= 0.0:
            txtContents.set(str(float(sqrt(eval(txtContents.get())))))
            print '           sqrt %s' % txtContents.get()
        else:
            print '        (Out of Function Domain in sqrt)'
    else:
        txtContents.set(str(float(eval(txtContents.get())**2)))
        print '            x^2 %s' % txtContents.get()
    intInv.set(0)
    stiffen = 1

def actCube():
    # If Inv is checked, input cube root of displayed number.
    # Otherwise, input cube of displayed number.
    global txtContents, operation, stiffen, intInv, intHyp, angGroup, __asinh__, __acosh__, __atanh__, parCapt, memCapt, par, memory, Fact
    if stiffen == 0:
        print '                %s' % txtContents.get()
    if intInv.get():
        if float(eval(txtContents.get())) >= 0.0:
            txtContents.set(str(float(eval(txtContents.get())**(1.0/3.0))))
            print '           curt %s' % txtContents.get()
        else:
            print '        (Out of Function Domain in curt)'
    else:
        txtContents.set(str(float(eval(txtContents.get())**3)))
        print '            x^3 %s' % txtContents.get()
    intInv.set(0)
    stiffen = 1

def actPow():
    # If Inv is checked, enter root into function.
    # Otherwise, enter x^y into function.
    global txtContents, operation, stiffen, intInv, intHyp, angGroup, __asinh__, __acosh__, __atanh__, parCapt, memCapt, par, memory, Fact
    if stiffen == 0:
        print '                %s' % txtContents.get()
    if intInv.get():
        print '               root'
        operation[par].append(txtContents.get())
        operation[par].append('root')
    else:
        print '               x^y'
        operation[par].append(txtContents.get())
        operation[par].append('x^y')
    intInv.set(0)
    stiffen = 1

def actSin():
    # If Inv is checked:
    #     If Hyp is checked, input area hyperbolic sine of displayed number.
    #     Otherwise, input arc sine of displayed number.
    # Otherwise:
    #     If Hyp is checked, input hyperbolic sine of displayed number.
    #     Otherwise, input sine of displayed number.
    global txtContents, operation, stiffen, intInv, intHyp, angGroup, __asinh__, __acosh__, __atanh__, parCapt, memCapt, par, memory, Fact
    if stiffen == 0:
        print '                %s' % txtContents.get()
    if intInv.get():
        if intHyp.get():
            txtContents.set(str(float(__asinh__(eval(txtContents.get())))))
            print '          asinh %s' % txtContents.get()
        else:
            if float(eval(txtContents.get())) <= 1.0 and float(eval(txtContents.get())) >= -1.0:
                if angGroup.get() == 'Deg':
                    txtContents.set(str(float(asin(eval(txtContents.get()))/pi*180)))
                    print '(Deg)      asin %s' % txtContents.get()
                elif angGroup.get() == 'Rad':
                    txtContents.set(str(float(asin(eval(txtContents.get())))))
                    print '(Rad)      asin %s' % txtContents.get()
                else:
                    txtContents.set(str(float(asin(eval(txtContents.get()))/pi*200)))
                    print '(Grad)     asin %s' % txtContents.get()
            else:
                print '        (Out of Function Domain in asin)'
    else:
        if intHyp.get():
            txtContents.set(str(float(sinh(eval(txtContents.get())))))
            print '           sinh %s' % txtContents.get()
        else:
            if angGroup.get() == 'Deg':
                txtContents.set(str(float(sin(eval(txtContents.get())*pi/180))))
                print '(Deg)       sin %s' % txtContents.get()
            elif angGroup.get() == 'Rad':
                txtContents.set(str(float(sin(eval(txtContents.get())))))
                print '(Rad)       sin %s' % txtContents.get()
            else:
                txtContents.set(str(float(sin(eval(txtContents.get())*pi/200))))
                print '(Grad)      sin %s' % txtContents.get()
    intInv.set(0)
    intHyp.set(0)
    stiffen = 1

def actCos():
    # If Inv is checked:
    #     If Hyp is checked, input area hyperbolic cosine of displayed number.
    #     Otherwise, input arc cosine of displayed number.
    # Otherwise:
    #     If Hyp is checked, input hyperbolic cosine of displayed number.
    #     Otherwise, input cosine of displayed number.
    global txtContents, operation, stiffen, intInv, intHyp, angGroup, __asinh__, __acosh__, __atanh__, parCapt, memCapt, par, memory, Fact
    if stiffen == 0:
        print '                %s' % txtContents.get()
    if intInv.get():
        if intHyp.get():
            if float(eval(txtContents.get())) >= 1.0:
                txtContents.set(str(float(__acosh__(eval(txtContents.get())))))
                print '          acosh %s' % txtContents.get()
            else:
                print '        (Out of Function Domain in acosh)'
        else:
            if float(eval(txtContents.get())) <= 1.0 and float(eval(txtContents.get())) >= -1.0:
                if angGroup.get() == 'Deg':
                    txtContents.set(str(float(acos(eval(txtContents.get()))/pi*180)))
                    print '(Deg)      acos %s' % txtContents.get()
                elif angGroup.get() == 'Rad':
                    txtContents.set(str(float(acos(eval(txtContents.get())))))
                    print '(Rad)      acos %s' % txtContents.get()
                else:
                    txtContents.set(str(float(acos(eval(txtContents.get()))/pi*200)))
                    print '(Grad)     acos %s' % txtContents.get()
            else:
                print '        (Out of Function Domain in acos)'
    else:
        if intHyp.get():
            txtContents.set(str(float(cosh(eval(txtContents.get())))))
            print '           cosh %s' % txtContents.get()
        else:
            if angGroup.get() == 'Deg':
                txtContents.set(str(float(cos(eval(txtContents.get())*pi/180))))
                print '(Deg)       cos %s' % txtContents.get()
            elif angGroup.get() == 'Rad':
                txtContents.set(str(float(cos(eval(txtContents.get())))))
                print '(Rad)       cos %s' % txtContents.get()
            else:
                txtContents.set(str(float(cos(eval(txtContents.get())*pi/200))))
                print '(Grad)      cos %s' % txtContents.get()
    intInv.set(0)
    intHyp.set(0)
    stiffen = 1

def actTan():
    # If Inv is checked:
    #     If Hyp is checked, input area hyperbolic tangent of displayed number.
    #     Otherwise, input arc tangent of displayed number.
    # Otherwise:
    #     If Hyp is checked, input hyperbolic tangent of displayed number.
    #     Otherwise, input tangent of displayed number.
    global txtContents, operation, stiffen, intInv, intHyp, angGroup, __asinh__, __acosh__, __atanh__, parCapt, memCapt, par, memory, Fact
    if stiffen == 0:
        print '                %s' % txtContents.get()
    if intInv.get():
        if intHyp.get():
            if float(eval(txtContents.get())) < 1.0 and float(eval(txtContents.get())) > -1.0:
                txtContents.set(str(float(__atanh__(eval(txtContents.get())))))
                print '          atanh %s' % txtContents.get()
            else:
                print '        (Out of Function Domain in atanh)'
        else:
            if angGroup.get() == 'Deg':
                txtContents.set(str(float(atan(eval(txtContents.get()))/pi*180)))
                print '(Deg)      atan %s' % txtContents.get()
            elif angGroup.get() == 'Rad':
                txtContents.set(str(float(atan(eval(txtContents.get())))))
                print '(Rad)      atan %s' % txtContents.get()
            else:
                txtContents.set(str(float(atan(eval(txtContents.get()))/pi*200)))
                print '(Grad)     atan %s' % txtContents.get()
    else:
        if intHyp.get():
            txtContents.set(str(float(tanh(eval(txtContents.get())))))
            print '           tanh %s' % txtContents.get()
        else:
            if angGroup.get() == 'Deg':
                if (float(eval(txtContents.get()))-90.0)/180.0 == float(int((float(eval(txtContents.get()))-90.0)/180.0)):
                    print '        (Out of Function Domain in tan)'
                else:
                    txtContents.set(str(float(tan(eval(txtContents.get())*pi/180))))
                    print '(Deg)       tan %s' % txtContents.get()
            elif angGroup.get() == 'Rad':
                if (float(eval(txtContents.get()))-pi/2)/pi == float(int((float(eval(txtContents.get()))-pi/2)/pi)):
                    print '        (Out of Function Domain in tan)'
                else:
                    txtContents.set(str(float(tan(eval(txtContents.get())))))
                    print '(Rad)       tan %s' % txtContents.get()
            else:
                if (float(eval(txtContents.get()))-100.0)/200.0 == float(int((float(eval(txtContents.get()))-100.0)/200.0)):
                    print '        (Out of Function Domain in tan)'
                else:
                    txtContents.set(str(float(tan(eval(txtContents.get())*pi/200))))
                    print '(Grad)      tan %s' % txtContents.get()
    intInv.set(0)
    intHyp.set(0)
    stiffen = 1

def actExp():
    # Allow user to enter a scientific notation exponent.  Best trial if 1 <= mantissa < 10.
    global txtContents, operation, stiffen, intInv, intHyp, angGroup, __asinh__, __acosh__, __atanh__, parCapt, memCapt, par, memory, Fact
    # Is there already an exponent?
    # See if adding e+0 and taking the eval jumps to the exception.
    if stiffen == 0:
        try:
            trial = eval('%se+0' % txtContents.get())
            txtContents.set('%se+0' % txtContents.get())
        except Exception, exponent:
            print '        (Incorrect place to put exponent)'
    else:
        print '        (Displayed number is read-only)'

def actDms():
    # If Inv is checked, convert from degrees-minutes-seconds to decimal degrees.
    # Otherwise, convert from decimal degrees to degrees-minutes-seconds.
    global txtContents, operation, stiffen, intInv, intHyp, angGroup, __asinh__, __acosh__, __atanh__, parCapt, memCapt, par, memory, Fact
    if stiffen == 0:
        print '                %s' % txtContents.get()
    if intInv.get():
        degrees = int(eval(txtContents.get()))
        minutes = int((eval(txtContents.get()) - int(eval(txtContents.get()))) * 100)
        seconds = (eval(txtContents.get()) * 100 - int(eval(txtContents.get()) * 100)) * 100
        txtContents.set(str(float(degrees + minutes / 60.0 + seconds / 3600.0)))
        print '     dms ==> dd %s' % txtContents.get()
    else:
        degrees = int(eval(txtContents.get()))
        minutes = int((eval(txtContents.get()) - int(eval(txtContents.get()))) * 60)
        seconds = (eval(txtContents.get()) * 60 - int(eval(txtContents.get()) * 60)) * 60
        txtContents.set(str(float(degrees + minutes / 100.0 + seconds / 10000.0)))
        print '     dd ==> dms %s' % txtContents.get()
    intInv.set(0)
    stiffen = 1

def actLeftP():
    # Open a new layer of parentheses.  Do not allow more than 25 layers.
    global txtContents, operation, stiffen, intInv, intHyp, angGroup, __asinh__, __acosh__, __atanh__, parCapt, memCapt, par, memory, Fact
    if par < 25:
        print '             ( ...'
        par += 1
        txtContents.set('0')
        stiffen = 1
        parCapt.set('PAR = %d' % par)
    else:
        print '        (Too many open levels of parentheses)'

def actRightP():
    # Close current innermost layer of parentheses.
    # On the other hand, use the order of operations to solve for the result of the expression grouped by this layer.
    global txtContents, operation, stiffen, intInv, intHyp, angGroup, __asinh__, __acosh__, __atanh__, parCapt, memCapt, par, memory, Fact
    if par > 0:
        operation[par].append(txtContents.get())
        if stiffen == 0:
            print '                %s' % txtContents.get()
        if len(operation[par]) > 1:
            for i in xrange(1, len(operation[par]), 2):
                if operation[par][i] == 'nCr':
                    if 0 <= int(eval(operation[par][i+1])) and int(eval(operation[par][i+1])) <= int(eval(operation[par][i-1])):
                        operation[par][i+1] = str(float(Fact(int(eval(operation[par][i-1]))))/float(Fact(int(eval(operation[par][i+1])))*Fact(int(eval(operation[par][i-1]))-int(eval(operation[par][i+1])))))
                        operation[par][i] = ''
                        operation[par][i-1] = ''
                    else:
                        print '        (Out of Function Domain in nCr)'
                elif operation[par][i] == 'nPr':
                    if 0 <= int(eval(operation[par][i+1])) and int(eval(operation[par][i+1])) <= int(eval(operation[par][i-1])):
                        operation[par][i+1] = str(float(Fact(int(eval(operation[par][i-1]))))/float(Fact(int(eval(operation[par][i-1]))-int(eval(operation[par][i+1])))))
                        operation[par][i] = ''
                        operation[par][i-1] = ''
                    else:
                        print '        (Out of Function Domain in nPr)'
            operation[par] = stringOut(operation[par])
        if len(operation[par]) > 1:
            for i in xrange(1, len(operation[par]), 2):
                if operation[par][i] == 'x^y':
                    if float(eval(operation[par][i-1])) == 0.0 and float(eval(operation[par][i+1])) < 0.0:
                        print '        (Out of Function Domain in x^y)'
                    elif float(eval(operation[par][i-1])) < 0.0 and float(eval(operation[par][i+1])) > float(int(eval(operation[par][i+1]))):
                        print '        (Out of Function Domain in x^y)'
                    else:
                        operation[par][i+1] = str(float(eval(operation[par][i-1]))**float(eval(operation[par][i+1])))
                        operation[par][i] = ''
                        operation[par][i-1] = ''
                elif operation[par][i] == 'root':
                    if float(eval(operation[par][i+1])) != 0.0:
                        if float(eval(operation[par][i-1])) == 0.0 and float(eval(operation[par][i+1])) < 0.0:
                            print '        (Out of Function Domain in root)'
                        elif float(eval(operation[par][i-1])) < 0.0 and 1.0/float(eval(operation[par][i+1])) > float(int(1.0/float(eval(operation[par][i+1])))):
                            print '        (Out of Function Domain in root)'
                        else:
                            operation[par][i+1] = str(float(eval(operation[par][i-1]))**(1.0/float(eval(operation[par][i+1]))))
                            operation[par][i] = ''
                            operation[par][i-1] = ''
                    else:
                        print '        (Division by Zero in root)'
            operation[par] = stringOut(operation[par])
        if len(operation[par]) > 1:
            for i in xrange(1, len(operation[par]), 2):
                if operation[par][i] == '*':
                    operation[par][i+1] = str(float(eval(operation[par][i-1]))*float(eval(operation[par][i+1])))
                    operation[par][i] = ''
                    operation[par][i-1] = ''
                elif operation[par][i] == '/':
                    if float(eval(operation[par][i+1])) != 0.0:
                        operation[par][i+1] = str(float(eval(operation[par][i-1]))/float(eval(operation[par][i+1])))
                        operation[par][i] = ''
                        operation[par][i-1] = ''
                    else:
                        print '        (Division by Zero in /)'
            operation[par] = stringOut(operation[par])
        if len(operation[par]) > 1:
            for i in xrange(1, len(operation[par]), 2):
                if operation[par][i] == '+':
                    operation[par][i+1] = str(float(eval(operation[par][i-1]))+float(eval(operation[par][i+1])))
                    operation[par][i] = ''
                    operation[par][i-1] = ''
                elif operation[par][i] == '-':
                    operation[par][i+1] = str(float(eval(operation[par][i-1]))-float(eval(operation[par][i+1])))
                    operation[par][i] = ''
                    operation[par][i-1] = ''
                elif operation[par][i] == 'Mod':
                    if float(eval(operation[par][i+1])) != 0.0:
                        operation[par][i+1] = str(float(eval(operation[par][i-1]))%float(eval(operation[par][i+1])))
                        operation[par][i] = ''
                        operation[par][i-1] = ''
                    else:
                        print '        (Modulo Zero in Mod)'
                elif operation[par][i] == 'And':
                    operation[par][i+1] = str(int(eval(operation[par][i-1]))&int(eval(operation[par][i+1])))
                    operation[par][i] = ''
                    operation[par][i-1] = ''
                elif operation[par][i] == 'Or':
                    operation[par][i+1] = str(int(eval(operation[par][i-1]))|int(eval(operation[par][i+1])))
                    operation[par][i] = ''
                    operation[par][i-1] = ''
                elif operation[par][i] == 'Xor':
                    operation[par][i+1] = str(int(eval(operation[par][i-1]))^int(eval(operation[par][i+1])))
                    operation[par][i] = ''
                    operation[par][i-1] = ''
                elif operation[par][i] == 'Lsh':
                    operation[par][i+1] = str(float(eval(operation[par][i-1]))*2**int(eval(operation[par][i+1])))
                    operation[par][i] = ''
                    operation[par][i-1] = ''
                elif operation[par][i] == 'Rsh':
                    operation[par][i+1] = str(float(eval(operation[par][i-1]))/2**int(eval(operation[par][i+1])))
                    operation[par][i] = ''
                    operation[par][i-1] = ''
            operation[par] = stringOut(operation[par])
        print '            ) = %s' % float(eval(operation[par][0]))
        txtContents.set(str(float(eval(operation[par][0]))))
        operation[par] = []
        par -= 1
        stiffen = 1
        if par > 0:
            parCapt.set('PAR = %d' % par)
        else:
            parCapt.set('')
    else:
        print '        (No open levels of parentheses to close)'

def actLn():
    # If Inv is checked, input the natural exponential function of the displayed number.
    # Otherwise, input the natural logarithm of the displayed number.
    global txtContents, operation, stiffen, intInv, intHyp, angGroup, __asinh__, __acosh__, __atanh__, parCapt, memCapt, par, memory, Fact
    if stiffen == 0:
        print '                %s' % txtContents.get()
    if intInv.get():
        txtContents.set(str(float(exp(eval(txtContents.get())))))
        print '            e^x %s' % txtContents.get()
    else:
        if float(eval(txtContents.get())) > 0.0:
            txtContents.set(str(float(log(eval(txtContents.get())))))
            print '             ln %s' % txtContents.get()
        else:
            print '        (Out of Function Domain in ln)'
    intInv.set(0)
    stiffen = 1

def actLog():
    # If Inv is checked, input the common exponential function of the displayed number.
    # Otherwise, input the common logarithm of the displayed number.
    global txtContents, operation, stiffen, intInv, intHyp, angGroup, __asinh__, __acosh__, __atanh__, parCapt, memCapt, par, memory, Fact
    if stiffen == 0:
        print '                %s' % txtContents.get()
    if intInv.get():
        txtContents.set(str(float(10**eval(txtContents.get()))))
        print '           10^x %s' % txtContents.get()
    else:
        if float(eval(txtContents.get())) > 0.0:
            txtContents.set(str(float(log10(eval(txtContents.get())))))
            print '            log %s' % txtContents.get()
        else:
            print '        (Out of Function Domain in log)'
    intInv.set(0)
    stiffen = 1

def actMod():
    # Enter modulo into function.
    global txtContents, operation, stiffen, intInv, intHyp, angGroup, __asinh__, __acosh__, __atanh__, parCapt, memCapt, par, memory, Fact
    if stiffen == 0:
        print '                %s' % txtContents.get()
    print '               Mod'
    operation[par].append(txtContents.get())
    operation[par].append('Mod')
    stiffen = 1

def actMC():
    # Clear any number stored in memory.
    global txtContents, operation, stiffen, intInv, intHyp, angGroup, __asinh__, __acosh__, __atanh__, parCapt, memCapt, par, memory, Fact
    memory = 0
    memCapt.set('')
    print '            (Memory cleared)'
    stiffen = 1

def actMR():
    # Input number stored in memory.
    global txtContents, operation, stiffen, intInv, intHyp, angGroup, __asinh__, __acosh__, __atanh__, parCapt, memCapt, par, memory, Fact
    txtContents.set(str(memory))
    print '         memory %s' % txtContents.get()
    stiffen = 1

def actMAdd():
    # Add displayed number to memory.  Do not display the sum of these numbers.
    global txtContents, operation, stiffen, intInv, intHyp, angGroup, __asinh__, __acosh__, __atanh__, parCapt, memCapt, par, memory, Fact
    memory += eval(txtContents.get())
    print '    add memory: %s' % txtContents.get()
    if float(memory) != 0.0:
        memCapt.set('MEMORY')
    else:
        memCapt.set('')
    stiffen = 1

def actMSub():
    # Subtract displayed number from memory.  Do not display the difference of these numbers.
    global txtContents, operation, stiffen, intInv, intHyp, angGroup, __asinh__, __acosh__, __atanh__, parCapt, memCapt, par, memory, Fact
    memory -= eval(txtContents.get())
    print '    sub memory: %s' % txtContents.get()
    if float(memory) != 0.0:
        memCapt.set('MEMORY')
    else:
        memCapt.set('')
    stiffen = 1

def actPosNeg():
    # Change the sign of the displayed number.  Special case for a scientific notation
    # exponent that the user is entering, and we must change the sign of the exponent.
    global txtContents, operation, stiffen, intInv, intHyp, angGroup, __asinh__, __acosh__, __atanh__, parCapt, memCapt, par, memory, Fact
    if stiffen == 1:
        txtContents.set(str(-float(eval(txtContents.get()))))
        print '            +/- %s' % txtContents.get()
    else:
        try:
            trial = eval('%se+0' % txtContents.get())
            if txtContents.get()[0] == '-':
                txtContents.set(txtContents.get()[1:len(txtContents.get())])
            else:
                txtContents.set('-%s' % txtContents.get())
        except Exception, exponent:
            i = 0
            for t in xrange(0, len(txtContents.get())):
                if txtContents.get()[t] == 'e':
                    i = t
            if txtContents.get()[i+1] == '-':
                txtContents.set('%s+%s' % (txtContents.get()[0:i+1], txtContents.get()[i+2:len(txtContents.get())]))
            else:
                txtContents.set('%s-%s' % (txtContents.get()[0:i+1], txtContents.get()[i+2:len(txtContents.get())]))

def actAnd():
    # Enter bitwise AND into function.
    global txtContents, operation, stiffen, intInv, intHyp, angGroup, __asinh__, __acosh__, __atanh__, parCapt, memCapt, par, memory, Fact
    if stiffen == 0:
        print '                %s' % txtContents.get()
    print '               And'
    operation[par].append(txtContents.get())
    operation[par].append('And')
    stiffen = 1

def actNot():
    # Input bitwise NOT of displayed number.  This operation depends on a bitrange,
    # and we must wrap around to the negative side where the answer is indepent of the bitrange.
    global txtContents, operation, stiffen, intInv, intHyp, angGroup, __asinh__, __acosh__, __atanh__, parCapt, memCapt, par, memory, Fact
    if stiffen == 0:
        print '                %s' % txtContents.get()
    txtContents.set(str(float(-1-int(eval(txtContents.get())))))
    print '            Not %s' % txtContents.get()
    stiffen = 1

def act7():
    # Enter digit 7.
    global txtContents, operation, stiffen, intInv, intHyp, angGroup, __asinh__, __acosh__, __atanh__, parCapt, memCapt, par, memory, Fact
    if stiffen == 1 or txtContents.get() == '0':
        txtContents.set('')
        stiffen = 0
    if len(txtContents.get()) >= 3:
        if txtContents.get()[-3:len(txtContents.get())] == 'e+0' or txtContents.get()[-3:len(txtContents.get())] == 'e-0':
            txtContents.set(txtContents.get()[0:-1])
    txtContents.set('%s7' % txtContents.get())

def act8():
    # Enter digit 8.
    global txtContents, operation, stiffen, intInv, intHyp, angGroup, __asinh__, __acosh__, __atanh__, parCapt, memCapt, par, memory, Fact
    if stiffen == 1 or txtContents.get() == '0':
        txtContents.set('')
        stiffen = 0
    if len(txtContents.get()) >= 3:
        if txtContents.get()[-3:len(txtContents.get())] == 'e+0' or txtContents.get()[-3:len(txtContents.get())] == 'e-0':
            txtContents.set(txtContents.get()[0:-1])
    txtContents.set('%s8' % txtContents.get())

def act9():
    # Enter digit 9.
    global txtContents, operation, stiffen, intInv, intHyp, angGroup, __asinh__, __acosh__, __atanh__, parCapt, memCapt, par, memory, Fact
    if stiffen == 1 or txtContents.get() == '0':
        txtContents.set('')
        stiffen = 0
    if len(txtContents.get()) >= 3:
        if txtContents.get()[-3:len(txtContents.get())] == 'e+0' or txtContents.get()[-3:len(txtContents.get())] == 'e-0':
            txtContents.set(txtContents.get()[0:-1])
    txtContents.set('%s9' % txtContents.get())

def actDiv():
    # Enter division into function.
    global txtContents, operation, stiffen, intInv, intHyp, angGroup, __asinh__, __acosh__, __atanh__, parCapt, memCapt, par, memory, Fact
    if stiffen == 0:
        print '                %s' % txtContents.get()
    print '                /'
    operation[par].append(txtContents.get())
    operation[par].append('/')
    stiffen = 1

def actOr():
    # Enter bitwise inclusive OR into function.
    global txtContents, operation, stiffen, intInv, intHyp, angGroup, __asinh__, __acosh__, __atanh__, parCapt, memCapt, par, memory, Fact
    if stiffen == 0:
        print '                %s' % txtContents.get()
    print '                Or'
    operation[par].append(txtContents.get())
    operation[par].append('Or')
    stiffen = 1

def actInt():
    # If Inv is checked, input the decimal portion of the displayed number.
    # Otherwise, TRUNCATE the decimal portion of the displayed number:
    # If positive, get down to the greatest integer less than or equal to the number.
    # If negative, get up to the least integer greater than or equal to the number.
    global txtContents, operation, stiffen, intInv, intHyp, angGroup, __asinh__, __acosh__, __atanh__, parCapt, memCapt, par, memory, Fact
    if stiffen == 0:
        print '                %s' % txtContents.get()
    if intInv.get():
        txtContents.set(str(float(eval(txtContents.get()))-int(eval(txtContents.get()))))
        print '           Frac %s' % txtContents.get()
    else:
        txtContents.set(str(int(eval(txtContents.get()))))
        print '            Int %s' % txtContents.get()
    intInv.set(0)
    stiffen = 1

def act4():
    # Enter digit 4.
    global txtContents, operation, stiffen, intInv, intHyp, angGroup, __asinh__, __acosh__, __atanh__, parCapt, memCapt, par, memory, Fact
    if stiffen == 1 or txtContents.get() == '0':
        txtContents.set('')
        stiffen = 0
    if len(txtContents.get()) >= 3:
        if txtContents.get()[-3:len(txtContents.get())] == 'e+0' or txtContents.get()[-3:len(txtContents.get())] == 'e-0':
            txtContents.set(txtContents.get()[0:-1])
    txtContents.set('%s4' % txtContents.get())

def act5():
    # Enter digit 5.
    global txtContents, operation, stiffen, intInv, intHyp, angGroup, __asinh__, __acosh__, __atanh__, parCapt, memCapt, par, memory, Fact
    if stiffen == 1 or txtContents.get() == '0':
        txtContents.set('')
        stiffen = 0
    if len(txtContents.get()) >= 3:
        if txtContents.get()[-3:len(txtContents.get())] == 'e+0' or txtContents.get()[-3:len(txtContents.get())] == 'e-0':
            txtContents.set(txtContents.get()[0:-1])
    txtContents.set('%s5' % txtContents.get())

def act6():
    # Enter digit 6.
    global txtContents, operation, stiffen, intInv, intHyp, angGroup, __asinh__, __acosh__, __atanh__, parCapt, memCapt, par, memory, Fact
    if stiffen == 1 or txtContents.get() == '0':
        txtContents.set('')
        stiffen = 0
    if len(txtContents.get()) >= 3:
        if txtContents.get()[-3:len(txtContents.get())] == 'e+0' or txtContents.get()[-3:len(txtContents.get())] == 'e-0':
            txtContents.set(txtContents.get()[0:-1])
    txtContents.set('%s6' % txtContents.get())

def actMult():
    # Enter multiplication into function.
    global txtContents, operation, stiffen, intInv, intHyp, angGroup, __asinh__, __acosh__, __atanh__, parCapt, memCapt, par, memory, Fact
    if stiffen == 0:
        print '                %s' % txtContents.get()
    print '                *'
    operation[par].append(txtContents.get())
    operation[par].append('*')
    stiffen = 1

def actXor():
    # Enter bitwise exclusive OR into function.
    global txtContents, operation, stiffen, intInv, intHyp, angGroup, __asinh__, __acosh__, __atanh__, parCapt, memCapt, par, memory, Fact
    if stiffen == 0:
        print '                %s' % txtContents.get()
    print '               Xor'
    operation[par].append(txtContents.get())
    operation[par].append('Xor')
    stiffen = 1

def actC():
    # Clear the displayed number only.
    global txtContents, operation, stiffen, intInv, intHyp, angGroup, __asinh__, __acosh__, __atanh__, parCapt, memCapt, par, memory, Fact
    txtContents.set('0')
    if stiffen == 1:
        print '            (Display cleared)'
    stiffen = 1

def act1():
    # Enter digit 1.
    global txtContents, operation, stiffen, intInv, intHyp, angGroup, __asinh__, __acosh__, __atanh__, parCapt, memCapt, par, memory, Fact
    if stiffen == 1 or txtContents.get() == '0':
        txtContents.set('')
        stiffen = 0
    if len(txtContents.get()) >= 3:
        if txtContents.get()[-3:len(txtContents.get())] == 'e+0' or txtContents.get()[-3:len(txtContents.get())] == 'e-0':
            txtContents.set(txtContents.get()[0:-1])
    txtContents.set('%s1' % txtContents.get())

def act2():
    # Enter digit 2.
    global txtContents, operation, stiffen, intInv, intHyp, angGroup, __asinh__, __acosh__, __atanh__, parCapt, memCapt, par, memory, Fact
    if stiffen == 1 or txtContents.get() == '0':
        txtContents.set('')
        stiffen = 0
    if len(txtContents.get()) >= 3:
        if txtContents.get()[-3:len(txtContents.get())] == 'e+0' or txtContents.get()[-3:len(txtContents.get())] == 'e-0':
            txtContents.set(txtContents.get()[0:-1])
    txtContents.set('%s2' % txtContents.get())

def act3():
    # Enter digit 3.
    global txtContents, operation, stiffen, intInv, intHyp, angGroup, __asinh__, __acosh__, __atanh__, parCapt, memCapt, par, memory, Fact
    if stiffen == 1 or txtContents.get() == '0':
        txtContents.set('')
        stiffen = 0
    if len(txtContents.get()) >= 3:
        if txtContents.get()[-3:len(txtContents.get())] == 'e+0' or txtContents.get()[-3:len(txtContents.get())] == 'e-0':
            txtContents.set(txtContents.get()[0:-1])
    txtContents.set('%s3' % txtContents.get())

def actSub():
    # Enter subtraction into function.
    global txtContents, operation, stiffen, intInv, intHyp, angGroup, __asinh__, __acosh__, __atanh__, parCapt, memCapt, par, memory, Fact
    if stiffen == 0:
        print '                %s' % txtContents.get()
    print '                -'
    operation[par].append(txtContents.get())
    operation[par].append('-')
    stiffen = 1

def actLsh():
    # If Inv is checked, enter bitwise right shift into function.
    # Otherwise, enter bitwise left shift into function.
    global txtContents, operation, stiffen, intInv, intHyp, angGroup, __asinh__, __acosh__, __atanh__, parCapt, memCapt, par, memory, Fact
    if stiffen == 0:
        print '                %s' % txtContents.get()
    if intInv.get():
        print '               Rsh'
        operation[par].append(txtContents.get())
        operation[par].append('Rsh')
    else:
        print '               Lsh'
        operation[par].append(txtContents.get())
        operation[par].append('Lsh')
    intInv.set(0)
    stiffen = 1

def actAC():
    # If Inv is checked, exit the calculator.
    # (This is like turning off a real hand-held calculator.
    #  This AC button could be the on button, labeled ON/AC.)
    # Otherwise, clear the entire operation.
    global txtContents, operation, stiffen, intInv, intHyp, angGroup, __asinh__, __acosh__, __atanh__, parCapt, memCapt, par, memory, Fact
    if intInv.get():
        print '======================================OFF======================================'
        quit()
    else:
        print '====================================CLEARED===================================='
        par = 0
        parCapt.set('')
        txtContents.set('0')
        operation = [[], [], [], [], [], [], [], [], [], [], [], [], [], [], [], [], [], [], [], [], [], [], [], [], [], []]
        stiffen = 1

def act0():
    # Enter digit 0.
    global txtContents, operation, stiffen, intInv, intHyp, angGroup, __asinh__, __acosh__, __atanh__, parCapt, memCapt, par, memory, Fact
    if stiffen == 1 or txtContents.get() == '0':
        txtContents.set('')
        stiffen = 0
    if len(txtContents.get()) >= 3:
        if txtContents.get()[-3:len(txtContents.get())] == 'e+0' or txtContents.get()[-3:len(txtContents.get())] == 'e-0':
            txtContents.set(txtContents.get()[0:-1])
    txtContents.set('%s0' % txtContents.get())

def actDec():
    # Enter a decimal point.
    global txtContents, operation, stiffen, intInv, intHyp, angGroup, __asinh__, __acosh__, __atanh__, parCapt, memCapt, par, memory, Fact
    # Do not want to be picky alright.  Only allow a decimal point if Python takes one.
    if stiffen == 1:
        txtContents.set('0.')
        stiffen = 0
    else:
        try:
            trial = eval('%s.0' % txtContents.get())
            txtContents.set('%s.' % txtContents.get())
        except Exception, note:
            print '        (Incorrect place to put decimal point)'

def actEq():
    # Use order of operations to solve for the result of the expression.
    # This button does not work if there are any open layers of parentheses.
    global txtContents, operation, stiffen, intInv, intHyp, angGroup, __asinh__, __acosh__, __atanh__, parCapt, memCapt, par, memory, Fact
    if par == 0:
        operation[par].append(txtContents.get())
        if stiffen == 0:
            print '                %s' % txtContents.get()
        if len(operation[par]) > 1:
            for i in xrange(1, len(operation[par]), 2):
                if operation[par][i] == 'nCr':
                    if 0 <= int(eval(operation[par][i+1])) and int(eval(operation[par][i+1])) <= int(eval(operation[par][i-1])):
                        operation[par][i+1] = str(float(Fact(int(eval(operation[par][i-1]))))/float(Fact(int(eval(operation[par][i+1])))*Fact(int(eval(operation[par][i-1]))-int(eval(operation[par][i+1])))))
                        operation[par][i] = ''
                        operation[par][i-1] = ''
                    else:
                        print '        (Out of Function Domain in nCr)'
                elif operation[par][i] == 'nPr':
                    if 0 <= int(eval(operation[par][i+1])) and int(eval(operation[par][i+1])) <= int(eval(operation[par][i-1])):
                        operation[par][i+1] = str(float(Fact(int(eval(operation[par][i-1]))))/float(Fact(int(eval(operation[par][i-1]))-int(eval(operation[par][i+1])))))
                        operation[par][i] = ''
                        operation[par][i-1] = ''
                    else:
                        print '        (Out of Function Domain in nPr)'
            operation[par] = stringOut(operation[par])
        if len(operation[par]) > 1:
            for i in xrange(1, len(operation[par]), 2):
                if operation[par][i] == 'x^y':
                    if float(eval(operation[par][i-1])) == 0.0 and float(eval(operation[par][i+1])) < 0.0:
                        print '        (Out of Function Domain in x^y)'
                    elif float(eval(operation[par][i-1])) < 0.0 and float(eval(operation[par][i+1])) > float(int(eval(operation[par][i+1]))):
                        print '        (Out of Function Domain in x^y)'
                    else:
                        operation[par][i+1] = str(float(eval(operation[par][i-1]))**float(eval(operation[par][i+1])))
                        operation[par][i] = ''
                        operation[par][i-1] = ''
                elif operation[par][i] == 'root':
                    if float(eval(operation[par][i+1])) != 0.0:
                        if float(eval(operation[par][i-1])) == 0.0 and float(eval(operation[par][i+1])) < 0.0:
                            print '        (Out of Function Domain in root)'
                        elif float(eval(operation[par][i-1])) < 0.0 and 1.0/float(eval(operation[par][i+1])) > float(int(1.0/float(eval(operation[par][i+1])))):
                            print '        (Out of Function Domain in root)'
                        else:
                            operation[par][i+1] = str(float(eval(operation[par][i-1]))**(1.0/float(eval(operation[par][i+1]))))
                            operation[par][i] = ''
                            operation[par][i-1] = ''
                    else:
                        print '        (Division by Zero in root)'
            operation[par] = stringOut(operation[par])
        if len(operation[par]) > 1:
            for i in xrange(1, len(operation[par]), 2):
                if operation[par][i] == '*':
                    operation[par][i+1] = str(float(eval(operation[par][i-1]))*float(eval(operation[par][i+1])))
                    operation[par][i] = ''
                    operation[par][i-1] = ''
                elif operation[par][i] == '/':
                    if float(eval(operation[par][i+1])) != 0.0:
                        operation[par][i+1] = str(float(eval(operation[par][i-1]))/float(eval(operation[par][i+1])))
                        operation[par][i] = ''
                        operation[par][i-1] = ''
                    else:
                        print '        (Division by Zero in /)'
            operation[par] = stringOut(operation[par])
        if len(operation[par]) > 1:
            for i in xrange(1, len(operation[par]), 2):
                if operation[par][i] == '+':
                    operation[par][i+1] = str(float(eval(operation[par][i-1]))+float(eval(operation[par][i+1])))
                    operation[par][i] = ''
                    operation[par][i-1] = ''
                elif operation[par][i] == '-':
                    operation[par][i+1] = str(float(eval(operation[par][i-1]))-float(eval(operation[par][i+1])))
                    operation[par][i] = ''
                    operation[par][i-1] = ''
                elif operation[par][i] == 'Mod':
                    if float(eval(operation[par][i+1])) != 0.0:
                        operation[par][i+1] = str(float(eval(operation[par][i-1]))%float(eval(operation[par][i+1])))
                        operation[par][i] = ''
                        operation[par][i-1] = ''
                    else:
                        print '        (Modulo Zero in Mod)'
                elif operation[par][i] == 'And':
                    operation[par][i+1] = str(int(eval(operation[par][i-1]))&int(eval(operation[par][i+1])))
                    operation[par][i] = ''
                    operation[par][i-1] = ''
                elif operation[par][i] == 'Or':
                    operation[par][i+1] = str(int(eval(operation[par][i-1]))|int(eval(operation[par][i+1])))
                    operation[par][i] = ''
                    operation[par][i-1] = ''
                elif operation[par][i] == 'Xor':
                    operation[par][i+1] = str(int(eval(operation[par][i-1]))^int(eval(operation[par][i+1])))
                    operation[par][i] = ''
                    operation[par][i-1] = ''
                elif operation[par][i] == 'Lsh':
                    operation[par][i+1] = str(float(eval(operation[par][i-1]))*2**int(eval(operation[par][i+1])))
                    operation[par][i] = ''
                    operation[par][i-1] = ''
                elif operation[par][i] == 'Rsh':
                    operation[par][i+1] = str(float(eval(operation[par][i-1]))/2**int(eval(operation[par][i+1])))
                    operation[par][i] = ''
                    operation[par][i-1] = ''
            operation[par] = stringOut(operation[par])
        print '              = %s' % float(eval(operation[par][0]))
        txtContents.set(str(float(eval(operation[par][0]))))
        operation[par] = []
        stiffen = 1
    else:
        if par != 1:
            plural = 's'
        else:
            plural = ''
        print '        (%s open level%s of parentheses)' % (par, plural)

def actAdd():
    # Enter addition into function.
    global txtContents, operation, stiffen, intInv, intHyp, angGroup, __asinh__, __acosh__, __atanh__, parCapt, memCapt, par, memory, Fact
    if stiffen == 0:
        print '                %s' % txtContents.get()
    print '                +'
    operation[par].append(txtContents.get())
    operation[par].append('+')
    stiffen = 1

##This is the heading of the trail of the calculator, which summarizes the
##entire operations you enter in.  For example, if you first submit the
##calculation 81 ^ -(3/4), then press AC, and then submit the calculation
##sqrt(4/pi), the trail would look like this:

# Python Calculator Trail
# ====================================CLEARED====================================
#                 81
#                x^y
#              ( ...
#                 3
#                 /
#                 4
#             ) = 0.75
#             +/- -0.75
#               = 0.037037037037
# ====================================CLEARED====================================
#              ( ...
#                 4
#                 /
#              pi 3.14159265359
#             ) = 1.27323954474
#            sqrt 1.1283791671

print 'Python Calculator Trail'
print '====================================CLEARED===================================='

chkInv = Checkbutton(root, text='Inv', width=2, variable=intInv).grid(row=2, column=0) # Inverse Function
chkHyp = Checkbutton(root, text='Hyp', width=2, variable=intHyp).grid(row=2, column=1) # Hyperbolic Function

# Angle Unit (Trigonometric Input)
angGroup = StringVar()
angGroup.set('Deg')
rdoDeg = Radiobutton(root, text='Deg', width=2, variable=angGroup, value='Deg').grid(row=2, column=3)
rdoRad = Radiobutton(root, text='Rad', width=2, variable=angGroup, value='Rad').grid(row=2, column=4)
rdoGrad = Radiobutton(root, text='Grad', width=3, variable=angGroup, value='Grad').grid(row=2, column=5)

# Buttons (8x6 array)

btnRand = Button(root, text='Rand', width=6, command=actRand).grid(row=3, column=0)
btnPi = Button(root, text='pi', width=6, command=actPi).grid(row=3, column=1)
btnFact = Button(root, text='x!', width=6, command=actFact).grid(row=3, column=2)
btnComb = Button(root, text='nCr', width=6, command=actComb).grid(row=3, column=3)
btnPerm = Button(root, text='nPr', width=6, command=actPerm).grid(row=3, column=4)
btnRec = Button(root, text='1/x', width=6, command=actRec).grid(row=3, column=5)

btnSqr = Button(root, text='x^2', width=6, command=actSqr).grid(row=4, column=0)
btnCube = Button(root, text='x^3', width=6, command=actCube).grid(row=4, column=1)
btnPow = Button(root, text='x^y', width=6, command=actPow).grid(row=4, column=2)
btnSin = Button(root, text='sin', width=6, command=actSin).grid(row=4, column=3)
btnCos = Button(root, text='cos', width=6, command=actCos).grid(row=4, column=4)
btnTan = Button(root, text='tan', width=6, command=actTan).grid(row=4, column=5)

btnExp = Button(root, text='Exp', width=6, command=actExp).grid(row=5, column=0)
btnDms = Button(root, text='dms', width=6, command=actDms).grid(row=5, column=1)
btnLeftP = Button(root, text='(', width=6, command=actLeftP).grid(row=5, column=2)
btnRightP = Button(root, text=')', width=6, command=actRightP).grid(row=5, column=3)
btnLn = Button(root, text='ln', width=6, command=actLn).grid(row=5, column=4)
btnLog = Button(root, text='log', width=6, command=actLog).grid(row=5, column=5)

btnMod = Button(root, text='Mod', width=6, command=actMod).grid(row=6, column=0)
btnMC = Button(root, text='MC', width=6, command=actMC).grid(row=6, column=1)
btnMR = Button(root, text='MR', width=6, command=actMR).grid(row=6, column=2)
btnMAdd = Button(root, text='M+', width=6, command=actMAdd).grid(row=6, column=3)
btnMSub = Button(root, text='M-', width=6, command=actMSub).grid(row=6, column=4)
btnPosNeg = Button(root, text='+/-', width=6, command=actPosNeg).grid(row=6, column=5)

btnAnd = Button(root, text='And', width=6, command=actAnd).grid(row=7, column=0)
btnNot = Button(root, text='Not', width=6, command=actNot).grid(row=7, column=1)
btn7 = Button(root, text='7', width=6, command=act7).grid(row=7, column=2)
btn8 = Button(root, text='8', width=6, command=act8).grid(row=7, column=3)
btn9 = Button(root, text='9', width=6, command=act9).grid(row=7, column=4)
btnDiv = Button(root, text='/', width=6, command=actDiv).grid(row=7, column=5)

btnOr = Button(root, text='Or', width=6, command=actOr).grid(row=8, column=0)
btnInt = Button(root, text='Int', width=6, command=actInt).grid(row=8, column=1)
btn4 = Button(root, text='4', width=6, command=act4).grid(row=8, column=2)
btn5 = Button(root, text='5', width=6, command=act5).grid(row=8, column=3)
btn6 = Button(root, text='6', width=6, command=act6).grid(row=8, column=4)
btnMult = Button(root, text='*', width=6, command=actMult).grid(row=8, column=5)

btnXor = Button(root, text='Xor', width=6, command=actXor).grid(row=9, column=0)
btnC = Button(root, text='C', width=6, command=actC).grid(row=9, column=1)
btn1 = Button(root, text='1', width=6, command=act1).grid(row=9, column=2)
btn2 = Button(root, text='2', width=6, command=act2).grid(row=9, column=3)
btn3 = Button(root, text='3', width=6, command=act3).grid(row=9, column=4)
btnSub = Button(root, text='-', width=6, command=actSub).grid(row=9, column=5)

btnLsh = Button(root, text='Lsh', width=6, command=actLsh).grid(row=10, column=0)
btnAC = Button(root, text='AC', width=6, command=actAC).grid(row=10, column=1)
btn0 = Button(root, text='0', width=6, command=act0).grid(row=10, column=2)
btnDec = Button(root, text='.', width=6, command=actDec).grid(row=10, column=3)
btnEq = Button(root, text='=', width=6, command=actEq).grid(row=10, column=4)
btnAdd = Button(root, text='+', width=6, command=actAdd).grid(row=10, column=5)

# Display MEMORY whenever a number is stored in memory.
lblMemory = Label(root, textvariable=memCapt).grid(row=0, column=3, columnspan=3)

# Show the current number of open levels of parentheses.  For example, if you press
# AC and enter: 3*(4+(2^6)/(5+3, have this button show PAR = 2, because there are 2 open
# levels of parentheses that are not closed.
lblParen = Label(root, textvariable=parCapt).grid(row=0, column=0, columnspan=3)

txtContents.set('0')
txtNum = Entry(root, textvariable=txtContents, state='readonly', justify=RIGHT, width=45).grid(row=1, column=0, columnspan=6)
# This is the display area, apart from the trail

root.mainloop()