Python
# Menu-driven calculator
print("1. Addition")
print("2. Subtraction")
print("3. Multiplication")
print("4. Division")
choice = input("Enter choice (1-4): ")
a = float(input("Enter first number: "))
b = float(input("Enter second number: "))
if choice == '1':
print("Result:", a + b)
elif choice == '2':
print("Result:", a - b)
elif choice == '3':
print("Result:", a * b)
elif choice == '4':
if b == 0:
print("Cannot divide by zero.")
else:
print("Result:", a / b)
else:
print("Invalid choice")Output
1. Addition 2. Subtraction 3. Multiplication 4. Division Enter choice (1-4): 1 Enter first number: 10 Enter second number: 5 Result: 15.0
This showcases a classic menu-driven program controlled by user input. We use a chain of elif to dispatch different arithmetic operations and guard against division by zero.