C++ Math scalbln()

scalbn(x,n) = x * ( FLT_RADX)n

float scalbln(float x, long int n);
double scalbln(double x, long int n);
long double scalbln(long double x, long int n);
double scalbln(integral x, long int n);

#include <iostream>
#include<math.h>
#include<float.h>
using namespace std;
int main()
{
 int x=3;
 long n=3L;
 std::cout << "Value of x is: " <<x<< std::endl;
 cout<<"3 * 2^3 = "<<scalbn(x,n);
return 0;
}

Value of x is: 3
3 * 2^3 = 24

#include <iostream>
#include<math.h>
#include<float.h>
using namespace std;
int main()
{
 float x=7.2;
 long n=2L;
 std::cout << "Value of x is : " <<x<< std::endl;
 cout<<"7.2 * 2^2 = "<<scalbln(x,n);
 return 0;
}

Value of x is : 7.2
7.2 * 2^2 = 28.8