1.Import Tkinter

import tkinter as tk

• This imports the tkinter module, allowing you to create GUI elements like windows, buttons, text fields, etc.

2.click(event) Function

def click(event):
    text = event.widget.cget("text")

• event.widget refers to the button that was clicked.

• .cget("text") gets the text label of the button (e.g., ‘7’, ‘+’, ‘=’, etc.).

    if text == "=":
        try:
            result = eval(str(entry.get()))
            entry.set(result)

• If the “=” button is clicked, it evaluates the current expression in the entry field using Python’s eval() function.

• The result is shown in the entry field.

• entry.set(result) updates the entry with the calculated result.

        except:
            entry.set("Error")

• If evaluation fails (e.g., invalid math), it shows "Error".

    elif text == "C":
        entry.set("")

• Clears the entry if "C" is clicked.

    else:
        entry.set(entry.get() + text)

• For any number/operator button, it appends that text to the current entry value.

 3.Create the Main Window

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

• Initializes the main application window and sets the window title.

4. Entry Field for Displaying Input/Output

entry = tk.StringVar()
entry_field = tk.Entry(root, textvar=entry, font="Arial 20")
entry_field.pack(fill="both", ipadx=8, pady=10, padx=10)

• StringVar() is used to dynamically update the entry box.

• Entry is the text input field where the math expression appears.

• pack() places it in the window with padding.

5.Calculator Buttons

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

• A list of lists to define the calculator layout row-wise.

for row in buttons:
    frame = tk.Frame(root)
    frame.pack()

• For each row, a separate Frame is created to arrange buttons horizontally.

    for btn in row:
        button = tk.Button(frame, text=btn, font="Arial 18", height=2, width=5)
        button.pack(side="left", padx=5, pady=5)
        button.bind("<Button-1>", click)

• A Button is created for each symbol in the row.

• pack(side="left") places buttons next to each other horizontally.

• bind("<Button-1>", click) links each button to the click() function on left mouse click.

 6.Run the Application

• This keeps the GUI running and listening for events like button clicks.