# Program : Menu-driven calculator

while True:
    print("\nMenu:")
    print("1. Addition")
    print("2. Subtraction")
    print("3. Multiplication")
    print("4. Division")
    print("5. Exit")

    choice = input("Enter choice: ")

    if choice == '5':
        print("Exiting program...")
        break

    a = float(input("Enter first number: "))
    b = float(input("Enter second number: "))

    if choice == '1':
        print(f"Result: {a + b}")
    elif choice == '2':
        print(f"Result: {a - b}")
    elif choice == '3':
        print(f"Result: {a * b}")
    elif choice == '4':
        if b != 0:
            print(f"Result: {a / b}")
        else:
            print("Error: Division by zero!")
    else:
        print("Invalid choice!")

 

# Program : Menu-driven calculator

def add(a, b):
    return a + b

def subtract(a, b):
    return a - b

def multiply(a, b):
    return a * b

def divide(a, b):
    if b == 0:
        return "Error: Cannot divide by zero!"
    return a / b

def main_menu():
    while True:
        print("\n--- Simple Calculator Menu ---")
        print("1. Add")
        print("2. Subtract")
        print("3. Multiply")
        print("4. Divide")
        print("5. Exit")

        choice = input("Enter your choice (1-5): ")

        if choice == '1':
            num1 = float(input("Enter first number: "))
            num2 = float(input("Enter second number: "))
            print(f"Result: {add(num1, num2)}")
        elif choice == '2':
            num1 = float(input("Enter first number: "))
            num2 = float(input("Enter second number: "))
            print(f"Result: {subtract(num1, num2)}")
        elif choice == '3':
            num1 = float(input("Enter first number: "))
            num2 = float(input("Enter second number: "))
            print(f"Result: {multiply(num1, num2)}")
        elif choice == '4':
            num1 = float(input("Enter first number: "))
            num2 = float(input("Enter second number: "))
            print(f"Result: {divide(num1, num2)}")
        elif choice == '5':
            print("Exiting calculator. Goodbye!")
            break
        else:
            print("Invalid choice. Please enter a number between 1 and 5.")

if __name__ == "__main__":
    main_menu()