Python Project Calculator using tkinter||AMIT SINGH

#calculator using Tkinter

 

# import everything from tkinter module

from tkinter import *

 

# globally declare the expression variable

expression = ""

 

 

# Function to update expressiom

# in the text entry box

def press(num):

    # point out the global expression variable

    global expression

 

    # concatenation of string

    expression = expression + str(num)

 

    # update the expression by using set method

    equation.set(expression)

 

 

# Function to evaluate the final expression

def equalpress():

    # Try and except statement is used

    # for handling the errors like zero

    # division error etc.

 

    # Put that code inside the try block

    # which may generate the error

    try:

 

        global expression

 

        # eval function evaluate the expression

        # and str function convert the result

        # into string

        total = str(eval(expression))

 

        equation.set(total)

 

        # initialze the expression variable

        # by empty string

        expression = ""

 

    # if error is generate then handle

    # by the except block

    except:

 

        equation.set(" error ")

        expression = ""

 

 

# Function to clear the contents

# of text entry box

def clear():

    global expression

    expression = ""

    equation.set("")

 

 

# Driver code

if __name__ == "__main__":

    # create a GUI window

    gui = Tk()

 

    # set the background colour of GUI window

    gui.configure(background="light green")

 

    # set the title of GUI window

    gui.title("Simple Calculator")

 

    # set the configuration of GUI window

    gui.geometry("270x150")

 

    # StringVar() is the variable class

    # we create an instance of this class

    equation = StringVar()

 

    # create the text entry box for

    # showing the expression .

    expression_field = Entry(gui, textvariable=equation)

 

    # grid method is used for placing

    # the widgets at respective positions

    # in table like structure .

    expression_field.grid(columnspan=4, ipadx=70)

 

    # create a Buttons and place at a particular

    # location inside the root window .

    # when user press the button, the command or

    # function affiliated to that button is executed .

    button1 = Button(gui, text=' 1 ', fg='black', bg='red',

                    command=lambda: press(1), height=1, width=7)

    button1.grid(row=2, column=0)

 

    button2 = Button(gui, text=' 2 ', fg='black', bg='red',

                    command=lambda: press(2), height=1, width=7)

    button2.grid(row=2, column=1)

 

    button3 = Button(gui, text=' 3 ', fg='black', bg='red',

                    command=lambda: press(3), height=1, width=7)

    button3.grid(row=2, column=2)

 

    button4 = Button(gui, text=' 4 ', fg='black', bg='red',

                    command=lambda: press(4), height=1, width=7)

    button4.grid(row=3, column=0)

 

    button5 = Button(gui, text=' 5 ', fg='black', bg='red',

                    command=lambda: press(5), height=1, width=7)

    button5.grid(row=3, column=1)

 

    button6 = Button(gui, text=' 6 ', fg='black', bg='red',

                    command=lambda: press(6), height=1, width=7)

    button6.grid(row=3, column=2)

 

    button7 = Button(gui, text=' 7 ', fg='black', bg='red',

                    command=lambda: press(7), height=1, width=7)

    button7.grid(row=4, column=0)

 

    button8 = Button(gui, text=' 8 ', fg='black', bg='red',

                    command=lambda: press(8), height=1, width=7)

    button8.grid(row=4, column=1)
press(9), height=1,  command=lambda: press(0), height=1, width=7)

    button0.grid(row=5, column=0)

 

    plus = Button(gui, text=' + ', fg='black', bg='red',

                command=lambda: press("+"), height=1, width=7)

    plus.grid(row=2, column=3)

 

    minus = Button(gui, text=' - ', fg='black', bg='red',

                command=lambda: press("-"), height=1, width=7)

    minus.grid(row=3, column=3)

 

    multiply = Button(gui, text=' * ', fg='black', bg='red',

                    command=lambda: press("*"), height=1, width=7)

    multiply.grid(row=4, column=3)

 

    divide = Button(gui, text=' / ', fg='black', bg='red',

                    command=lambda: press("/"), height=1, width=7)

    divide.grid(row=5, column=3)

 

    equal = Button(gui, text=' = ', fg='black', bg='red',

                command=equalpress, height=1, width=7)

    equal.grid(row=5, column=2)

 

    clear = Button(gui, text='Clear', fg='black', bg='red',

                command=clear, height=1, width=7)

    clear.grid(row=5, column='1')

 

    Decimal= Button(gui, text='.', fg='black', bg='red',

                    command=lambda: press('.'), height=1, width=7)

    Decimal.grid(row=6, column=0)

    # start the GUI

    gui.mainloop()