Factorial of a Number Using For Loop in Java: Code & Algorithm

A program to find factorial for an integer data-type using for loop in JAVA

Algorithm for Factorial

Step 1: Start
Step 2: Read a number n
Step 3: Initialize variables: i = 1, result = 1
Step 4: if i <= n go to Step 4 otherwise go to Step 7
Step 5: Calculate result = result * i
Step 6: Increment the i by 1 (i = i + 1) and go to Step 3
Step 7: Display result
Step 8: Stop

As 1 is an identity for multiplication i.e whenever any number is multiply with 1, same value is obtained. For e.g 7 * 1 = 7 Thats why we assign result = 1 as initial value

Working example

/**
 * Factorial for N using FOR loop
 */
class FactorialDemoUsingForLoop
{
    public static void main(String[] args)
    {
        int i, result = 1, n = 5;

        for (i = 1; i <= n; i += 1)
        {
            // System.out.println("I: " + i);
            // System.out.println("Result B4: " + result);
            result *= i;
            // System.out.println("Result After: "+ result);
        }

        System.out.println("Factorial of " + n + ": " + result);
    }
}

Output for number 5

Factorial of 5: 120