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 <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 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 <complex>
using namespace std;

const double EPS = 1e-6;
typedef complex<double> Point;

double cross(Point a, Point b){
    return (conj(a)*b).imag();
}

int main(){
    Point V[3], P;
    while(!cin.eof()){
        for(int i=0; i<3; i++){
            double x, y; cin >> x >> y;
            V[i] = {x, y};
        }
        double x, y; cin >> x >> y;
        P = {x, y};
        
        int sum1 = 0, sum2 = 0;
        for(int i=0; i<3; i++){
            int x = cross(V[(i+1)%3]-V[i], (P-V[i]));
            sum1 += x<0;
            sum2 += x>0;
        }
        cout << (sum1 == 3 || sum2 == 3? "YES": "NO") << endl;
    }
    return 0;
}

C++: #include "bits/stdc++.h"
#include <cassert>
using namespace std;
typedef long long ll;
typedef pair<int,int> pii;
#define rep(i,n) for(ll i=0;i<(ll)(n);i++)
#define all(a)  (a).begin(),(a).end()
#define vi vector<int>
#define pb push_back
#define INF 999999999
//#define INF (1LL<<59)



#define EPS (1e-10)
class P{                    //???
public:
    double x,y;
    
    P(double _x=0,double _y=0):x(_x),y(_y){};
    P operator + (P &p     ){ return P( x+p.x , y+p.y ); }  //??????
    P operator - (P &p     ){ return P( x-p.x , y-p.y ); }  //??????
    P operator * (double k ){ return P( x*k   , y*k    ); } //??????
    P operator / (double k ){ return P( x/k   , y/k    ); } //??????
    
    bool operator == (const P &p){ return ( fabs(x-p.x)<EPS && fabs(y-p.y)<EPS ); }
    //    bool operator < (const P &p)const{ return ( x!=p.x ? x<p.x:y<p.y ); }
    
    double norm(){ return x*x+y*y; }        //?????????
    double abs() { return sqrt(norm()); }   //??§??????
    
};
struct L{P p1,p2;};         //??´???
typedef vector<P> Polygon;  //????§???¢
typedef P Vector;           //????????????

double dot  (Vector a,Vector b){ return a.x*b.x+a.y*b.y; }
double cross(Vector a,Vector b){ return a.x*b.y-a.y*b.x; }

int ccw(P p0,P p1,P p2){    //AOJ_BOOK_P386 verified
    Vector a = p1 - p0;
    Vector b = p2 - p0;
    
    if( cross(a,b) > EPS  ) return 1 ;      //COUNTER_CLOCKWISE
    if( cross(a,b) < -EPS ) return -1;      //CLOCKWISE
    if( dot(a,b)   < -EPS ) return 2;       //ONLINE_BACK
    if( a.norm()   < b.norm() ) return -2;  //ONLINE_FRONT
    
    return 0;                               //ON_SEGMENT;
}

//?????????????????? verified
bool intersect(P p1,P p2,P p3,P p4){ return ( ccw(p1,p2,p3)*ccw(p1,p2,p4)<=0 && ccw(p3,p4,p1)*ccw(p3,p4,p2)<=0 ); }

//????????¨???????????¢ verified ARC042-B
double distance_l_p(L l, P p) { return abs(cross(l.p2-l.p1, p-l.p1)) /(l.p2-l.p1).abs(); }

//????????¨??????????????????(????????£???????????´??????????????±???)
bool intersect_circle_point(P center, double r, L line){
    if( distance_l_p(line,center) <= r+EPS ) return true;
    return false;
}


//????´?????§???¢??????
bool isSimple( Polygon pol ){
    //???????????????????????????pol?????\????????????
    size_t pol_size = pol.size()-1;
    rep(i,pol_size){
        for(int j=i+2;j<pol_size;j++){
            if( i==j || i==(j-1+pol_size)%pol_size || i==(j+1+pol_size)%pol_size )continue;
            if( intersect(pol[i], pol[i+1], pol[j], pol[j+1]) )return false;
        }
    }
    return true;
}


//?????????????§???¢????????´?????????????????????????±??????? true???????????´ verified AOJ0012
bool isPointInsidePolygon(vector<L> side,P p){
    int c=0, sideSum=side.size();
    
    rep(i,sideSum){
        if( cross(side[i].p2-side[i].p1,p-side[i].p1)>0 ) c++;
    }
    return !(c%sideSum);
}


int main(){
    double a,b,c,d,e,f,g,h;
    while(cin>>a>>b>>c>>d>>e>>f>>g>>h){
        vector<L> angle;
        angle.pb( L{P(a,b),P(c,d)} );
        angle.pb( L{P(c,d),P(e,f)} );
        angle.pb( L{P(e,f),P(a,b)} );
        
        if(isPointInsidePolygon(angle,P(g,h))){
            cout<<"YES"<<endl;
        }
        else cout<<"NO"<<endl;
    }
    
    
    return 0;
}