Compute Lowest Common Multiple (LCM) of Two Numbers in Java

Exercise:

Write a Java Program to find the Lowest Common Multiple (LCM) of two numbers.

1.Calculate using While loop

Click Here to View the Solution!
public class LCMFinder {
   public static void main(String[] args) {
  
     int num1 = 60, num2 = 240, lcm;
  
     // maximum number between n1 and n2 is stored in lcm
     lcm = (num1 > num2) ? num1 : num2;
  
     // Always true
     while(true) {
       if( lcm % num1 == 0 && lcm % num2 == 0 ) {
         System.out.printf("The LCM of %d and %d is %d.", num1, num2, lcm);
         break;
       }
       ++lcm;
     }
   }
} 
Click Here to View the Output!
The LCM of 60 and 240 is 240.
Click Here to View the Explanation!
  • This program is used for finding the Lowest Common Multiple (LCM) of two numbers by using the while loop.
  • Initially, two integer numbers num1 and num2 are initialized as num1 = 60 and num2 = 240 of which the lcm needs to be found.
  • Since, the value of LCM must be greater or equal to the largest number, the initial value of the variable lcm is set to be the largest of the two numbers num1 and num2.
  • For the lcm of two numbers, it should have zero remainder with both numbers. Therefore, in the infinite while loop, the value of lcm is checked to find out whether it is exactly divisible by the two numbers.
  • If the lcm is found, the program can break out of the loop and print the output else, the value of lcm is incremented, and the while loop is run again. This is done until the lcm is found.
  • In the end, the LCM is displayed on the screen.

2. CALCULATE USING GCD

Click Here to View the Solution!
public class LCMFinder {
   public static void main(String[] args) {
  
     int num1 = 60, num2 = 240, gcd = 1;
  
     for(int i = 1; i <= num1 && i <= num2; ++i) 
    {
       // Condition to check if i is factor of both numbers
       if(num1 % i == 0 && num2 % i == 0)
         gcd = i;
     }
  
     int lcm = (num1 * num2) / gcd;
     System.out.printf("The LCM of %d and %d is %d.", num1, num2, lcm);
   }
} 
Click Here to View the Output!
The LCM of 60 and 240 is 240.
Click Here to View the Explanation!
  • This program is used for finding the LCM of two numbers by using their GCD. It uses the while and for loop.
  • Initially, two numbers, num1 and num2 are initialized as num1 = 60 and num2 = 240 of which the gcd and lcm is to be found. And another variable gcd is initialized as gcd = 1.
  • The gcd of the two numbers is calculated through a condition set in the for loop.
  • After the gcd is found, the lcm of the two numbers is found using the following formula: (num1 * num2) / gcd.
  • As a result, the LCM of the given two numbers are displayed on the screen.