Python Calculator

Simple Python Calculator

A clean command-line calculator built with Python. Performs basic arithmetic operations with error handling.

What It Does

This calculator lets you:

• Add, subtract, multiply, and divide numbers
• Handle decimals and negative numbers
• Prevent crashes from bad input
• Run multiple calculations without restarting

How It Works

The Functions

Each math operation gets its own function:

def add(x, y):
    return x + y

def divide(x, y):
    if y == 0:
        return "Error! Division by zero."
    return x / y

Why separate functions? Makes the code easy to test and reuse.

The Menu Loop

The calculator runs in a loop, showing a menu each time:

1. Add
2. Subtract
3. Multiply
4. Divide
5. Exit

Users pick a number, enter two values, and get their answer. Press 5 to exit.

Error Handling

Two types of errors are handled:

1. Division by zero - Returns an error message instead of crashing
2. Invalid input - Catches when users type letters instead of numbers

try:
    num1 = float(input("Enter first number: "))
except ValueError:
    print("Invalid input! Please enter numbers only.")

Key Features

✓ Simple menu interface

✓ Works with decimals (3.14, 2.5)

✓ Works with negatives (-5, -10)

✓ Doesn't crash on bad input

✓ Only 50 lines of code

Usage Example

Enter choice (1/2/3/4/5): 1
Enter first number: 10
Enter second number: 5
10.0 + 5.0 = 15.0

What I Learned

Building this taught me:

• Writing clean functions
• Handling user input safely
• Using loops for repeated actions
• Managing errors without crashes

Possible Improvements

Ideas for future versions:

• Add more operations (square root, power)
• Save calculation history
• Add a memory function
• Create a GUI version

Running the Code

python calculator.py

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Tech: Python 3

Lines of Code: ~50

View the complete code on GitHub: Simple-Calculator

Simple, functional, and ready to use.