Go: package main

import "fmt"

func main() {
	var x1, x2, x3, y1, y2, y3, xp, yp float64
	for {
		v, _ := fmt.Scanf("%f %f %f %f %f %f %f %f", &x1, &y1, &x2, &y2, &x3, &y3, &xp, &yp)
		// println(x1, x2, x3, y1, y2, y3, xp, yp)
		if v != 8 {
			break
		}
		ok1 := true
		ok2 := true
		if (x2-x1)*(yp-y1)-(xp-x1)*(y2-y1)<0 {
			ok1 = false
		} else {
			ok2 = false
		}
		if (x3-x2)*(yp-y2)-(xp-x2)*(y3-y2)<0 {
			ok1 = false
		} else {
			ok2 = false
		}
		if (x1-x3)*(yp-y3)-(xp-x3)*(y1-y3)<0 {
			ok1 = false
		} else {
			ok2 = false
		}
		if ok1 || ok2 {
			fmt.Println("YES")
		} else {
			fmt.Println("NO")
		}
	}
}

C++: #include<iostream>
#include<cmath>
using namespace std;

void couten(double x[], double y[], double &cx, double &cy){
	double a2, b2, c2, a, b, c, s, S2;
	a2 = abs((x[2]-x[1])*(x[2]-x[1]) + (y[2]-y[1])*(y[2]-y[1]));
    b2 = abs((x[0]-x[2])*(x[0]-x[2]) + (y[0]-y[2])*(y[0]-y[2]));
    c2 = abs((x[1]-x[0])*(x[1]-x[0]) + (y[1]-y[0])*(y[1]-y[0]));
    a = sqrt(a2); b = sqrt(b2); c = sqrt(c2);
	if((a + b + c) == 0){
		s = 0;
		cx = 0;
		cy = 0;
	} else{
		s = (a + b + c) / 2;S2 = s * (s-a) * (s-b) * (s-c);
		cx = (a2*(b2+c2-a2)*x[0] + b2*(c2+a2-b2)*x[1] + c2*(a2+b2-c2)*x[2]) / (16 * S2);
		cy = (a2*(b2+c2-a2)*y[0] + b2*(c2+a2-b2)*y[1] + c2*(a2+b2-c2)*y[2]) / (16 * S2);
	}
}

int hantei(double x[], double y[], double &cx, double &cy, double xp, double yp){
	bool flag[3];
	double tc, tp, tcc, tpp;
	x[3] = x[0]; y[3] = y[0];
	for(int i = 0; i < 3; i++){
		tc = (x[i] - x[i + 1]) * (cy - y[i]) + (y[i] - y[i + 1]) * (x[i] - cx);
		tp = (x[i] - x[i + 1]) * (yp - y[i]) + (y[i] - y[i + 1]) * (x[i] - xp);
		if(tc * tp >= 0){
			flag[i] = true;
		} else{
			continue;
		}
	}
	if(flag[0] == true && flag[1] == true && flag[2] == true){
		return 1;
	} else{
		return 0;
	}
}


int main(){
	double x[3], y[3], xp, yp, cxx, cyy;
	double &cx = cxx, &cy = cyy;
	
	while(cin >>x[0] >>y[0] >>x[1] >>y[1] >>x[2] >>y[2] >>xp >>yp){
		couten(x, y, cx, cy);
		if(hantei(x, y, cx, cy, xp, yp)){
			cout <<"YES"<<endl;
		} else{
			cout <<"NO"<<endl;
		}
	}
	
	return 0;
}

C++: #include <bits/stdc++.h>
using namespace std ;

#define pb(n) push_back(n)
#define fi first
#define se second
#define X real()
#define Y imag()
#define all(r) (r).begin(),(r).end()
#define gsort(st,en) sort((st),(en),greater<int>())
#define vmax(ary) *max_element(all(ary))
#define vmin(ary) *min_element(all(ary))
#define debug(x) cout<<#x<<": "<<x<<endl
#define fcout(n) cout<<fixed<<setprecision((n))
#define scout(n) cout<<setw(n)
#define vary(type,name,size,init) vector< type> name(size,init)

#define rep(i,n) for(int i = 0; i < (int)(n);++i)
#define REP(i,a,b) for(int i = (a);i < (int)(b);++i)
#define repi(it,array) for(auto it = array.begin(),end = array.end(); it != end;++it)
#define repa(n,array) for(auto &n :(array))

using ll = long long;
using vi = vector<int>;
using vl = vector<ll>;
using dict = map<string,int>;
using comd = complex<double>;
using pii = pair<int,int> ;

constexpr int imax = ((1<<30)-1)*2+1 ;
constexpr int inf = 100000000;
constexpr double PI = acos(-1.0) ;
double eps = 1e-10 ;
const int dy[] = {-1,0,1,0};
const int dx[] = {0,-1,0,1};

inline bool value(int x,int y,int w,int h){
  return (x >= 0 && x < w && y >= 0 && y < h);
}

double CalcDist(comd p1, comd p2){
  return sqrt(pow(p1.X - p2.X,2.0) + pow(p1.Y -p2.Y,2.0));
}

template<typename T>
void Unique(vector<T> &v){
  sort(all(v));
  v.erase(all(v),v.end());
}

template<typename T>
T ston(string& str, T n){
  istringstream sin(str) ;
  T num ;
  sin >> num ;
  return num ;
}

void Ans(bool f){
  if(f) cout << "YES"<<endl;
  else cout << "NO"<<endl;
}

double EPS = 1e-10;
double add(double a, double b){
  if(abs(a+b) < EPS* (abs(a) + abs(b))) return 0;
  return a+b;
}
struct P{
  double x,y;
  P(){}
  P(double _x,double _y):x(_x),y(_y){}
  P operator + (P p){
    return P(add(x,p.x) ,add(y,p.y));
  }
  P operator - (P p){
    return P(add(x,-p.x) ,add(y,-p.y));
  }
  P operator * (double d){
    return P(x * d,y * d);
  }
  double norm(){
    return sqrt(x*x + y*y);
  }
  double dot(P p){
    return add(x * p.x,y*p.y);
  }
  double det(P p){
    return add(x*p.y,-y*p.x);
  }
  double dist2(P p){
    return ((*this-p).x * (*this-p).x) + ((*this-p).y * (*this-p).y);
  }
  double GetSlope(P &p){
    P tmp = *this - p;
    return tmp.y/tmp.x;
  }
};
//????????????????????????¨?????????
bool on_seg(P p1,P p2,P q){
  return (p1-q).det(p2-q) == 0 && (p1-q).dot(p2-q) <= 0;
}

bool check(P p1,P p2,P p3, P p4){
  P a = p1 - p2,b = p3 - p2, p = p4 - p2;
  double theta1 = acos(a.dot(b)/(a.norm() * b.norm()));
  double theta2 = acos(b.dot(a)/(a.norm() * b.norm()));
  double thetap = acos(a.dot(p)/(a.norm() * p.norm()));
  double thetaq = acos(b.dot(p)/(a.norm() * p.norm()));
  //   debug(theta1);
  //   debug(theta2);
  //   debug(thetap);
  //   debug(thetaq);
  return thetap <= theta1 && thetaq <= theta1;
}

int main(){
  cin.tie(0);
  ios::sync_with_stdio(false);
  double a,b,c,d,e,f,xp,yp;
  while(cin >> a >> b >> c >> d >> e >> f >> xp >> yp){
    bool flag = true;
    //     double acx = c-a,abx = e-a,acy = d-b,aby = f-b,apx = xp-a,apy = yp - b;
    P p1 = P(a,b),p2 = P(c,d),p3 = P(e,f),p4 = P(xp,yp);
    Ans(check(p1,p2,p3,p4) && check(p1,p3,p2,p4) && check(p3,p1,p2,p4));
  }
  return 0;
}

C++: #include<iostream>
#include<algorithm>

using namespace std;
#define EPS (1e-10)
struct L{
    L(double xa, double ya, double xb, double yb){
	x1 = xa;
	y1 = ya;
	x2 = xb;
	y2 = yb;
	if(xa-xb == 0){
	    a = 1;
	    b = 0;
	    c = -xa;
	}
	else {
	    a = (ya-yb);
	    b = (xb-xa);
	    c = -(a*xa + b*ya);
	}
    };
    double f(double x, double y){
	return a*x + b*y + c;
    }
    double a, b, c, x1, x2, y1, y2;//0 = ax + by + c [x1, x2]
};

bool cross(L a, L b){
    return (a.f(b.x1, b.y1) * a.f(b.x2, b.y2) < 0+EPS && 
	    b.f(a.x1, a.y1) * b.f(a.x2, a.y2) < 0+EPS);
}

double x1, y1, x2, y2, x3, y3, xp, yp;

int main(){
    while(cin){
	cin >> x1 >> y1 >> x2 >> y2>> x3 >> y3 >> xp >> yp;
	L a = L(x1, y1, x2, y2);
	L b = L(x1, y1, x3, y3);
	L c = L(x2, y2, x3, y3);
	L p = L(xp, yp, 203, 103.141592);
	int res = 0;
	if(cross(a,p))res++;
	if(cross(b,p))res++;
	if(cross(c,p))res++;
	if(res % 2 == 0)cout << "NO" <<  endl;
	else cout << "YES"<<endl;
    }
    return 0;
}

C++: #include "bits/stdc++.h"

#define debug(x) cout<<#x<<": "<<x<<endl
#define rep(i,n) for (int i=0;i<(n);i++)
#define FOR(i,a,b) for (int i=(a);i<=(b);i++)
#define all(a) (a).begin(),(a).end()
using namespace std;
typedef vector<int> VI;
typedef vector<vector<int>> VVI;
typedef long long ll;

bool isAbove(pair<double, double> p1, pair<double, double> p2, pair<double, double> p3) {
	if (p1.first == p2.first) {
		return p3.first > p1.first;
	} else {
		return p3.second > p1.second + (p2.second - p1.second) * (p3.first - p1.first) / (p2.first - p1.first);
	}
}

void solve() {
#ifdef _WIN32
	istream &cin = ifstream("input.txt");
#endif

	vector<pair<double, double>> vertices(4);
	while (cin >> vertices[0].first) {
		cin >> vertices[0].second;
		rep(i, 3) cin >> vertices[i + 1].first >> vertices[i + 1].second;

		bool flag = (isAbove(vertices[0], vertices[1], vertices[2]) == isAbove(vertices[0], vertices[1], vertices[3]));
		flag &= (isAbove(vertices[0], vertices[2], vertices[1]) == isAbove(vertices[0], vertices[2], vertices[3]));
		flag &= (isAbove(vertices[1], vertices[2], vertices[0]) == isAbove(vertices[1], vertices[2], vertices[3]));

		cout << (flag ? "YES" : "NO") << endl;
	}


}




int main() {
	cin.tie(0);
	ios::sync_with_stdio(false);


	solve();
	return 0;
}