from tkinter import *

root = Tk()
root.title("Simple Calculator")

e = Entry(root, width=40, borderwidth=3)

def button_click(number):
    entry = e.get()
    entry = str(entry) +  str(number)
    e.delete(0, END)
    e.insert(0, entry)

def button_clear():
    e.delete(0, END)

def button_add():
    first_number = e.get()
    global f_num
    global math 
    math = "Addition"
    a_num = int(first_number)
    e.delete(0 , END)
    
def button_sub():
    first_number = e.get()
    global f_num
    global math 
    math = "Subtraction"
    f_num = int(first_number)
    e.delete(0, END)

def button_pro():
    first_number = e.get()
    global f_num
    global math 
    math = "Product"
    f_num = int(first_number)
    e.delete(0, END)

def button_div():
    first_number = e.get()
    global f_num
    global math 
    math = "Division" 
    f_num = int(first_number)
    e.delete(0, END)    

def button_equal():
    second_num = e.get()
    e.delete(0, END)
    if math == "Addition":
        e.insert(0, f_num + int(second_num))

    if math == "Subtraction":    
        e.insert(0, f_num - int(second_num))   
    
    if math == "Product":    
        e.insert(0, f_num * int(second_num)) 
    
    if math == "Division":
        e.insert(0, f_num / int(second_num)) 

# defining buttons
button_1 = Button(root, text="1", padx=40, pady=30, command= lambda :button_click(1))
button_2 = Button(root, text="2", padx=40, pady=30, command=lambda :button_click(2))
button_3 = Button(root, text="3", padx=40, pady=30, command=lambda :button_click(3))
button_4 = Button(root, text="4", padx=40, pady=30, command=lambda :button_click(4))
button_5 = Button(root, text="5", padx=40, pady=30, command=lambda :button_click(5))
button_6 = Button(root, text="6", padx=40, pady=30, command=lambda :button_click(6))
button_7 = Button(root, text="7", padx=40, pady=30, command=lambda :button_click(7))
button_8 = Button(root, text="8", padx=40, pady=30, command=lambda :button_click(8))
button_9 = Button(root, text="9", padx=40, pady=30, command=lambda :button_click(9))
button_0 = Button(root, text="0", padx=40, pady=30, command=lambda :button_click(0))
button_add = Button(root, text="+", padx=40, pady=30, command=button_add)
button_sub = Button(root, text="-", padx=40, pady=30, command=button_sub)
button_pro = Button(root, text="*", padx=40, pady=30, command=button_pro)
button_div = Button(root, text="/", padx=40, pady=30, command=button_div)
button_equal = Button(root, text="=", padx=90, pady=30, command=button_equal)
button_clear = Button(root, text="clear", padx=80, pady=15, command=button_clear)


#placing Items
e.grid(row=0, column=0, columnspan=4, padx=10, pady=15)

button_1.grid(row=4, column =0)
button_2.grid(row=4, column =1)
button_3.grid(row=4, column =2)
button_4.grid(row=3, column =0)
button_5.grid(row=3, column =1)
button_6.grid(row=3, column =2)
button_7.grid(row=2, column =0)
button_8.grid(row=2, column =1)
button_9.grid(row=2, column =2)
button_0.grid(row=5, column =0)

button_equal.grid(row=5, column =1, columnspan=2)
button_clear.grid(row=1, column=2, columnspan=3)

button_add.grid(row=5, column=3)
button_sub.grid(row=4, column=3)
button_pro.grid(row=3, column=3)
button_div.grid(row=2, column=3)




root.mainloop()