Java program to find LCM of two numbers

Well, today you will be learning java program to find LCM of two numbers.

java program to find LCM of two numbers

LCM is one of the common interview question in java. Well, first let us understand what is LCM??

Least Common Multiple(LCM)

Least Common Multiple of two integers a and b is the smallest non zero positive integer that is divisible by both a and b.

Here in the below java program, two numbers are stored in two variables. We have to set lcm to largest of two numbers since lcm cannot be less than largest number between two numbers.

Also read – java find GCD and LCM using euclid’s algorithm

In while loop we check if lcm divides two numbers. If two numbers divides, LCM is found. Else increment lcm by 1.

Java program to find lcm of two numbers

Now let’s see java program to find the LCM of two numbers,

public class LCMOfTwoNumber
{
   public static void main(String[] args)
   { 
      int num1 = 85, num2 = 175, lcm;
      lcm = (num1 > num2) ? num1 : num2;
      while(true)
      {
         if(lcm % num1 == 0 && lcm % num2 == 0)
         {
            System.out.printf("LCM of " + num1 + " and " + num2 + " is " + lcm + ".");
            break;
         }
         ++lcm;
      }
   }
}

Output:

LCM of 85 and 175 is 2975.

To find lcm of two numbers we can use gcd. Here’s the formula,

LCM = (num1 * num2) / GCD

public class LCMUsingGCD 
{
   public static void main(String[] args) 
   {
      int num1 = 15, num2 = 25, gcd = 1;
      for(int a = 1; a <= num1 && a <= num2; ++a)
      {
         if(num1 % a == 0 && num2 % a == 0)
         {
            gcd = a;
         }
      }
      int lcm = (num1 * num2) / gcd;
      System.out.printf("LCM of " + num1 + " and " + num2 + " is " + lcm + ".");
   }
}

Output:

LCM of 15 and 25 is 75.