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Author: captain-noob

calculator.py

@@ -0,0 +1,161 @@
+# Python program to create a simple GUI
+# 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("265x125")
+
+	# 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)
+
+	equation.set('enter your expression')
+
+	# 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)
+
+	button9 = Button(gui, text=' 9 ', fg='black', bg='red',
+					command=lambda: press(9), height=1, width=7)
+	button9.grid(row=4, column=2)
+
+	button0 = Button(gui, text=' 0 ', fg='black', bg='red',
+					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')
+
+	# start the GUI
+	gui.mainloop()