# -*- coding: utf-8 -*- 
#author: Cullen 
 
#import the module 
from Tkinter import * 
import tkFont 
import os 
from functools import partial 
from PIL import Image, ImageTk 
 
def get_input(entry, argu): 
  entry.insert(END, argu) 
 
def backspace(entry): 
  input_len = len(entry.get()) 
  entry.delete(input_len - 1) 
 
def clear(entry): 
  entry.delete(0, END) 
 
def calc(entry): 
  input = entry.get() 
  output = str(eval(input.strip())) 
  clear(entry) 
  entry.insert(END, output) 
 
def cal(): 
  root = Tk() 
  root.title("Calc") 
  root.resizable(0,0) 
 
  entry_font = tkFont.Font(size=12) 
  entry = Entry(root, justify="right", font=entry_font) 
  entry.grid(row=0, column=0, columnspan=4, sticky=N+W+S+E, padx=5, pady=5) 
 
  button_font = tkFont.Font(size=10, weight=tkFont.BOLD) 
  button_bg = '#D5E0EE' 
  button_active_bg = '#E5E35B' 
 
  myButton = partial(Button, root, bg=button_bg, padx=10, pady=3, activebackground = button_active_bg) 
 
  button7 = myButton(text='7', command=lambda : get_input(entry, '7')) 
  button7.grid(row=1, column=0, pady=5) 
 
  button8 = myButton(text='8', command=lambda : get_input(entry, '8')) 
  button8.grid(row=1, column=1, pady=5) 
 
  button9 = myButton(text='9', command=lambda : get_input(entry, '9')) 
  button9.grid(row=1, column=2, pady=5) 
 
  button10 = myButton(text='+', command=lambda : get_input(entry, '+')) 
  button10.grid(row=1, column=3, pady=5) 
 
  button4 = myButton(text='4', command=lambda : get_input(entry, '4')) 
  button4.grid(row=2, column=0, pady=5) 
 
  button5 = myButton(text='5', command=lambda : get_input(entry, '5')) 
  button5.grid(row=2, column=1, pady=5) 
 
  button6 = myButton(text='6', command=lambda : get_input(entry, '6')) 
  button6.grid(row=2, column=2, pady=5) 
 
  button11 = myButton(text='-', command=lambda : get_input(entry, '-')) 
  button11.grid(row=2, column=3, pady=5) 
 
  button1 = myButton(text='1', command=lambda : get_input(entry, '1')) 
  button1.grid(row=3, column=0, pady=5) 
 
  button2 = myButton(text='2', command=lambda : get_input(entry, '2')) 
  button2.grid(row=3, column=1, pady=5) 
 
  button3 = myButton(text='3', command=lambda : get_input(entry, '3')) 
  button3.grid(row=3, column=2, pady=5) 
 
  button12 = myButton(text='*', command=lambda : get_input(entry, '*')) 
  button12.grid(row=3, column=3, pady=5) 
 
  button0 = myButton(text='0', command=lambda : get_input(entry, '0')) 
  button0.grid(row=4, column=0, columnspan=2, padx=3, pady=5, sticky=N+S+E+W) 
 
  button13 = myButton(text='.', command=lambda : get_input(entry, '.')) 
  button13.grid(row=4, column=2, pady=5) 
 
  button14 = Button(root, text='/', bg=button_bg, padx=10, pady=3, 
           command=lambda : get_input(entry, '/')) 
  button14.grid(row=4, column=3, pady=5) 
 
  button15 = Button(root, text='<-', bg=button_bg, padx=10, pady=3, 
           command=lambda : backspace(entry), activebackground = button_active_bg) 
  button15.grid(row=5, column=0, pady=5) 
 
  button16 = Button(root, text='C', bg=button_bg, padx=10, pady=3, 
           command=lambda : clear(entry), activebackground = button_active_bg) 
  button16.grid(row=5, column=1, pady=5) 
 
  button17 = Button(root, text='=', bg=button_bg, padx=10, pady=3, 
           command=lambda : calc(entry), activebackground = button_active_bg) 
  button17.grid(row=5, column=2, columnspan=2, padx=3, pady=5, sticky=N+S+E+W) 
 
  root.mainloop() 
 
if __name__ == '__main__': 
  cal()