from tkinter import *
from decimal import *
root = Tk()
root.title('Calculator')
buttons = (('7', '8', '9', '/', '4'),
('4', '5', '6', '*', '4'),
('1', '2', '3', '-', '4'),
('0', '.', '=', '+', '4')
)
activeStr = ''
stack = []
def calculate():
global stack
global label
result = 0
operand2 = Decimal(stack.pop())
operation = stack.pop()
operand1 = Decimal(stack.pop())
if operation == '+':
result = operand1 + operand2
if operation == '-':
result = operand1 - operand2
if operation == '/':
result = operand1 / operand2
if operation == '*':
result = operand1 * operand2
label.configure(text=str(result))
def click(text):
global activeStr
global stack
if text == 'CE':
stack.clear()
activeStr = ''
label.configure(text='0')
elif '0' <= text <= '9':
activeStr += text
label.configure(text=activeStr)
elif text == '.':
if activeStr.find('.') == -1:
activeStr += text
label.configure(text=activeStr)
else:
if len(stack) >= 2:
stack.append(label['text'])
calculate()
stack.clear()
stack.append(label['text'])
activeStr = ''
if text != '=':
stack.append(text)
else:
if text != '=':
stack.append(label['text'])
stack.append(text)
activeStr = ''
label.configure(text='0')
label = Label(root, text='0', width=35)
label.grid(row=0, column=0, columnspan=4, sticky="nsew")
button = Button(root, text='CE', command=lambda text='CE': click(text))
button.grid(row=1, column=3, sticky="nsew")
for row in range(4):
for col in range(4):
button = Button(root, text=buttons[row][col],
command=lambda row1=row, col1=col: click(buttons[row1][col1]))
button.grid(row=row + 2, column=col, sticky="nsew")
root.grid_rowconfigure(6, weight=1)
root.grid_columnconfigure(4, weight=1)
root.mainloop()
