Task 2- 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! Division by zero."
    else:
        return a / b

def main():
    print("\t *****Simple Calculator*****")
    print("\nSelect operation:")
    print("1. Add")
    print("2. Subtract")
    print("3. Multiply")
    print("4. Divide")

    while True:
        choice = input("Enter choice (1/2/3/4): ")

        if choice in ('1', '2', '3', '4'):
            try:
                num1 = float(input("Enter first number: "))
                num2 = float(input("Enter second number: "))
            except ValueError:
                print("Invalid input. Please enter numerical values.")
                continue

            if choice == '1':
                print(f"{num1} + {num2} = {add(num1, num2)}")
            elif choice == '2':
                print(f"{num1} - {num2} = {subtract(num1, num2)}")
            elif choice == '3':
                print(f"{num1} * {num2} = {multiply(num1, num2)}")
            elif choice == '4':
                print(f"{num1} / {num2} = {divide(num1, num2)}")

            next_calculation = input("Do you want to perform another calculation? (y/n): ")
            if next_calculation.lower() != 'y':
                break
        else:
            print("Invalid choice. Please select a valid operation.")

if __name__ == "__main__":
    main()