Tkinter :Calculator in Python

 import tkinter as tk

def button_click(number):

    current = entry.get()

    entry.delete(0, tk.END)

    entry.insert(tk.END, current + number)

def button_clear():

    entry.delete(0, tk.END)

def button_equal():

    try:

        result = eval(entry.get())

        entry.delete(0, tk.END)

        entry.insert(tk.END, str(result))

    except:

        entry.delete(0, tk.END)

        entry.insert(tk.END, "Error")

def main():

    root = tk.Tk()

    root.title("Calculator")

    

    entry = tk.Entry(root, width=20, font=("Helvetica", 12))

    entry.grid(row=0, column=0, columnspan=4)

    buttons = [

        '7', '8', '9', '/',

        '4', '5', '6', '*',

        '1', '2', '3', '-',

        '0', '.', '=', '+'

    ]

    

    row = 1

    col = 0

    for button in buttons:

        if button == '=':

            tk.Button(root, text=button, width=5, command=button_equal).grid(row=row, column=col)

        elif button == 'C':

            tk.Button(root, text=button, width=5, command=button_clear).grid(row=row, column=col)

        else:

            tk.Button(root, text=button, width=5, command=lambda b=button: button_click(b)).grid(row=row, column=col)

        col += 1

        if col > 3:

            col = 0

            row += 1

    root.mainloop()

if __name__ == "__main__":

    main()