Project Euler 45

#include <iostream>
#include <cmath>
using namespace std;
int incr = 286;
int s = 40755;
bool esTriangular(int n)
{
    while(s<n)
        s+=incr, incr++;
    return s == n;
}
bool esPentagonal(int x)
{
    double n = (sqrt(24.0*x + 1)+1)/6.0;
    return n==floor(n);
}
int main()
{
    int hexa;
    int id=144 ;
    while(true)
    {
        hexa = id*(2*id -1 );
        if(esPentagonal(hexa) && esTriangular(hexa))
        {
            cout << hexa<<endl;
            return 0;
        }
        id++;
    }
    return 0;
}