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Creating a calculator with a graphical user interface (GUI)

Creating a calculator with a graphical user interface (GUI) is a bit more involved, but it can be a great learning experience. We'll use the tkinter library, which comes with Python by default, to create the GUI. Here's a step-by-step guide:



  1. Import tkinter: Start by importing the tkinter library and creating the main window.


import tkinter as tk

# Create the main window
root = tk.Tk()
root.title("Calculator")
  1. Create Display: Create a display field where the user inputs and results will be shown.


display = tk.Entry(root, width=20, borderwidth=5)
display.grid(row=0, column=0, columnspan=4)
  1. Define Button Click Function: Create a function that handles button clicks and updates the display.


def button_click(number):
    current = display.get()
    display.delete(0, tk.END)
    display.insert(0, current + str(number))
  1. Create Buttons: Create buttons for numbers (0-9) and basic operations (+, -, *, /).


buttons = [
    '7', '8', '9', '/',
    '4', '5', '6', '*',
    '1', '2', '3', '-',
    '0', '.', '=', '+'
]

row_val = 1
col_val = 0for button in buttons:
    tk.Button(root, text=button, padx=20, pady=20,
              command=lambda b=button: button_click(b) if b != '=' else calculate()).grid(row=row_val, column=col_val)
    col_val += 1if col_val > 3:
        col_val = 0
        row_val += 1
        
  1. Implement Calculation: Create a function to perform calculations when the '=' button is clicked.


def calculate():
    expression = display.get()
    try:
        result = eval(expression)
        display.delete(0, tk.END)
        display.insert(0, result)
    except:
        display.delete(0, tk.END)
        display.insert(0, "Error")
  1. Run the GUI: Run the GUI loop to start the calculator application.


root.mainloop()

The complete code should look like this:


import tkinter as tk

def button_click(number):
    current = display.get()
    display.delete(0, tk.END)
    display.insert(0, current + str(number))

def calculate():
    expression = display.get()
    try:
        result = eval(expression)
        display.delete(0, tk.END)
        display.insert(0, result)
    except:
        display.delete(0, tk.END)
        display.insert(0, "Error")

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

display = tk.Entry(root, width=20, borderwidth=5)
display.grid(row=0, column=0, columnspan=4)

buttons = [
    '7', '8', '9', '/',
    '4', '5', '6', '*',
    '1', '2', '3', '-',
    '0', '.', '=', '+'
]

row_val = 1
col_val = 0for button in buttons:
    tk.Button(root, text=button, padx=20, pady=20,
              command=lambda b=button: button_click(b) if b != '=' else calculate()).grid(row=row_val, column=col_val)
    col_val += 1if col_val > 3:
        col_val = 0
        row_val += 1

root.mainloop()

Save this code to a .py file and run it using your Python interpreter. It will open a simple calculator GUI with number buttons and basic arithmetic operations. You can expand upon this by adding more functionality, error handling, and a polished design.

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