Calculator Program in Python with Code and Output

Introduction

A Calculator Program in Python is a simple beginner-level Python project that performs basic arithmetic operations such as addition, subtraction, multiplication, and division. It is a good program for students who are learning Python because it demonstrates variables, input, conditional statements, functions, and operators.

In this article, we will learn how to create a calculator program in Python with source code, explanation, sample output, and a simple version for beginners.

Calculator Program in Python

Here is a simple Python calculator program:

# Calculator Program in Pythonnum1 = float(input("Enter first number: "))operator = input("Enter operator (+, -, *, /): ")num2 = float(input("Enter second number: "))if operator == "+":    result = num1 + num2    print("Result:", result)elif operator == "-":    result = num1 - num2    print("Result:", result)elif operator == "*":    result = num1 * num2    print("Result:", result)elif operator == "/":    if num2 != 0:        result = num1 / num2        print("Result:", result)    else:        print("Error: Cannot divide by zero.")else:    print("Invalid operator.")

Output

Example 1: Addition

Enter first number: 20
Enter operator (+, -, *, /): +
Enter second number: 10
Result: 30.0

Example 2: Subtraction

Enter first number: 50
Enter operator (+, -, *, /): -
Enter second number: 20
Result: 30.0

Example 3: Multiplication

Enter first number: 10
Enter operator (+, -, *, /): *
Enter second number: 5
Result: 50.0

Example 4: Division

Enter first number: 100
Enter operator (+, -, *, /): /
Enter second number: 4
Result: 25.0

How the Program Works

The program first asks the user to enter the first number.

num1 = float(input("Enter first number: "))

The float() function allows the user to enter both whole numbers and decimal numbers.

Next, the program asks the user to select an operator:

operator = input("Enter operator (+, -, *, /): ")

The second number is then entered:

num2 = float(input("Enter second number: "))

The if-elif statements determine which mathematical operation should be performed.

For addition:

if operator == "+":    result = num1 + num2

For subtraction:

elif operator == "-":    result = num1 - num2

For multiplication:

elif operator == "*":    result = num1 * num2

For division:

elif operator == "/":    result = num1 / num2

The program also checks whether the user is trying to divide by zero.

if num2 != 0:

This prevents a division-by-zero error.

Calculator Program Using Functions

A cleaner version can be created using functions:

def add(a, b):    return a + bdef subtract(a, b):    return a - bdef multiply(a, b):    return a * bdef divide(a, b):    if b == 0:        return "Cannot divide by zero"    return a / bnum1 = float(input("Enter first number: "))operator = input("Enter operator (+, -, *, /): ")num2 = float(input("Enter second number: "))if operator == "+":    print("Result:", add(num1, num2))elif operator == "-":    print("Result:", subtract(num1, num2))elif operator == "*":    print("Result:", multiply(num1, num2))elif operator == "/":    print("Result:", divide(num1, num2))

Advantages of This Program

• Easy for beginners to understand
• Demonstrates Python operators
• Uses input() and print()
• Demonstrates if-elif-else
• Can handle decimal numbers
• Handles division by zero
• Can be extended into a GUI calculator

Conclusion

The Calculator Program in Python is a useful beginner project for understanding basic Python programming concepts. After learning this program, students can extend it by adding percentage, modulus, power, square root, multiple calculations, loops, or a graphical user interface using Tkinter.