how c++ sqrt work? code example

Example 1: sqrt in c++

#include <cmath>
sqrt(x);

Example 2: sqrt cpp

#include <math.h>

//get square root of a number "b"
int main(){
  	int a = 2; //declare number you want to take square root of
  	int sqrtNum = sqrt (a); //assign the sqrt value to a variable
  	cout << sqrtNum << endl;
	return 0;
}