from tkinter import *

class MenuDemo:
    def __init__(self):
        window = Tk()
        window.title("Menu Demo")
        
        # Create a menu bar
        menubar = Menu(window)
        window.config(menu = menubar) # Display the menu bar
        
        # create a pulldown menu, and add it to the menu bar
        operationMenu = Menu(menubar, tearoff = 0)
        menubar.add_cascade(label = "Operation", menu = operationMenu)
        operationMenu.add_command(label = "Add",  
            command = self.add)
        operationMenu.add_command(label = "Subtract", 
            command = self.subtract)
        operationMenu.add_separator()
        operationMenu.add_command(label = "Multiply", 
            command = self.multiply)
        operationMenu.add_command(label = "Divide", 
            command = self.divide)
        
        # create more pulldown menus
        exitmenu = Menu(menubar, tearoff = 0)
        menubar.add_cascade(label = "Exit", menu = exitmenu)
        exitmenu.add_command(label = "Quit", command = window.quit)
        
        # Add a tool bar frame 
        frame0 = Frame(window) # Create and add a frame to window
        frame0.grid(row = 1, column = 1, sticky = W)
        
        # Create images
        plusImage = PhotoImage(file = "image/plus.gif")
        minusImage = PhotoImage(file = "image/minus.gif")
        timesImage = PhotoImage(file = "image/times.gif")
        divideImage = PhotoImage(file = "image/divide.gif")
        
        Button(frame0, image = plusImage, command = 
            self.add).grid(row = 1, column = 1, sticky = W)
        Button(frame0, image = minusImage,
            command = self.subtract).grid(row = 1, column = 2)
        Button(frame0, image = timesImage,  
            command = self.multiply).grid(row = 1, column = 3)
        Button(frame0, image = divideImage, 
            command = self.divide).grid(row = 1, column = 4)
        
        # Add labels and entries to frame1
        frame1 = Frame(window)
        frame1.grid(row = 2, column = 1, pady = 10)
        Label(frame1, text = "Number 1:").pack(side = LEFT)
        self.v1 = StringVar()
        Entry(frame1, width = 5, textvariable = self.v1, 
              justify = RIGHT).pack(side = LEFT)
        Label(frame1, text = "Number 2:").pack(side = LEFT)
        self.v2 = StringVar()
        Entry(frame1, width = 5, textvariable = self.v2, 
              justify = RIGHT).pack(side = LEFT)
        Label(frame1, text = "Result:").pack(side = LEFT)
        self.v3 = StringVar()
        Entry(frame1, width = 5, textvariable = self.v3, 
              justify = RIGHT).pack(side = LEFT)
        
        # Add buttons to frame2
        frame2 = Frame(window) # Create and add a frame to window
        frame2.grid(row = 3, column = 1, pady = 10, sticky = E)
        Button(frame2, text = "Add", command = self.add).pack(
            side = LEFT)
        Button(frame2, text = "Subtract", 
               command = self.subtract).pack(side = LEFT)
        Button(frame2, text = "Multiply", 
               command = self.multiply).pack(side = LEFT)
        Button(frame2, text = "Divide", 
               command = self.divide).pack(side = LEFT)
               
        mainloop()
        
    def add(self): 
        self.v3.set(eval(self.v1.get()) + eval(self.v2.get()))
    
    def subtract(self):
        self.v3.set(eval(self.v1.get()) - eval(self.v2.get()))
    
    def multiply(self):
        self.v3.set(eval(self.v1.get()) * eval(self.v2.get()))
    
    def divide(self):
        self.v3.set(eval(self.v1.get()) / eval(self.v2.get()))

MenuDemo() # Create GUI