how to find lcm of two numbers in cpp

// C++ program to find LCM of two numbers  
#include <iostream>  
using namespace std; 
  
// Recursive function to return gcd of a and b  
class gfg 
{ 
public :  
  int gcd(int a, int b){ 
    if (a == 0) 
        return b;  
    return gcd(b % a, a);  
 } 
  
   
  // Function to return LCM of two numbers  
  int lcm(int a, int b)  
  {  
     return (a*b)/gcd(a, b);  
  }  
} ; 
// Driver program to test above function  
int main()  
{  
    gfg g; 
    int a = 15, b = 20;  
    cout<<"LCM of "<<a<<" and "<<b<<" is "<<g.lcm(a, b);  
    return 0;  
}