Multiply Integer Pairs Without Using the Multiplication Operator

Program Overview

This Python program reads multiple pairs of integers from the user.
For each pair, it calculates the product without using the * operator.
The program continues until the user enters two zeros, which signals termination.

Python Code:

def multiply(a, b):
    result = 0
    negative = False

    if b < 0:
        b = -b
        negative = True

    for _ in range(b):
        result += a

    return -result if negative else result

while True:
    x = int(input("Enter the first number: "))
    y = int(input("Enter the second number: "))

    if x == 0 and y == 0:
        print("Program terminated.")
        break

    product = multiply(x, y)
    print("The product is:", product)

Sample Output:

Enter the first number: 4
Enter the second number: 3
The product is: 12

Enter the first number: -2
Enter the second number: 5
The product is: -10

Enter the first number: 0
Enter the second number: 0
Program terminated.

Explanation:

Here’s how the program works:
- The multiply() function uses repeated addition to simulate multiplication
- If the second number is negative, the result is negated
- The loop continues until both inputs are zero
- Results are displayed using the print() function