Calculator.py

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


def subtract(x, y):
    return x - y


def multiply(x, y):
    return x * y


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


def main():
    print("Simple Calculator")
    print("=================")
    print("1. Add")
    print("2. Subtract")
    print("3. Multiply")
    print("4. Divide")
    print("0. Exit")

    while True:
        choice = input("\nEnter choice (1/2/3/4/0): ")

        if choice == "0":
            print("Goodbye!")
            break

        if choice not in ("1", "2", "3", "4"):
            print("Invalid choice, try again.")
            continue

        try:
            num1 = float(input("Enter first number: "))
            num2 = float(input("Enter second number: "))
        except ValueError:
            print("Invalid number, please enter numeric values.")
            continue

        if choice == "1":
            result = add(num1, num2)
            op = "+"
        elif choice == "2":
            result = subtract(num1, num2)
            op = "-"
        elif choice == "3":
            result = multiply(num1, num2)
            op = "*"
        else:
            result = divide(num1, num2)
            op = "/"

        print(f"Result: {num1} {op} {num2} = {result}")


if __name__ == "__main__":
    main()