Лежит точка внутри треугольника

#include <iostream>
#include <cmath>

using namespace std;
double area(double ax,double ay,double bx,double by,double cx,double cy) {
    return abs((by-ay)*(cx-ax)-(bx-ax)*(cy-ay));
}
bool resh(double ax, double ay, double bx, double by, double cx, double cy, double px, double py){
    double s=area(ax,ay,bx,by,cx,cy),s1=area(ax,ay,bx,by,px,py),s2=area(bx,by,cx,cy,px,py),s3=area(cx,cy,ax,ay,px,py);
    if (s1+s2+s3-s<=0) return true; else return false;
}
int main()
{
    double pointx, pointy;
    cin >> pointx >> pointy;
    // resh(точка A, точка B, точка C, произвольная точка)   ( по две координаты)
    if(resh(1,1,2,1,1.5,2,pointx, pointy) or resh(1,2,2,2,1.5,3,pointx, pointy) or resh(1,3,2,3,1.5,4,pointx, pointy)) cout << "Yes";

    return 0;
}