Language: Java

import java.util.*;

public class Main{
	private static final Scanner scan = new Scanner(System.in);

	public static void main(String[] args){
		List<String> list = new ArrayList<String>();
		while(scan.hasNext()){
			x1 = scan.nextDouble();
			y1 = scan.nextDouble();
			x2 = scan.nextDouble();
			y2 = scan.nextDouble();
			x3 = scan.nextDouble();
			y3 = scan.nextDouble();
			xp = scan.nextDouble();
			yp = scan.nextDouble();
			double S_pab = Math.abs((x1 - xp) * (y2 - yp) - (x2 - xp) * (y1 - yp));
			double S_pac = Math.abs((x1 - xp) * (y3 - yp) - (x3 - xp) * (y1 - yp));
			double S_pbc = Math.abs((x2 - xp) * (y3 - yp) - (x3 - xp) * (y2 - yp));
			double S_abc = Math.abs((x3 - x1) * (y2 - y1) - (x2 - x1) * (y3 - y1));
			if(S_abc == S_pab + S_pac + S_pbc){
				list.add("YES");
			} else{
				list.add("NO");
			}
		}

		for(String s : list){
			System.out.printf("%s\n", s);
		}
	}
}

Compiler output:
Main.java:9: error: cannot find symbol
			x1 = scan.nextDouble();
			^
  symbol:   variable x1
  location: class Main
Main.java:10: error: cannot find symbol
			y1 = scan.nextDouble();
			^
  symbol:   variable y1
  location: class Main
Main.java:11: error: cannot find symbol
			x2 = scan.nextDouble();
			^
  symbol:   variable x2
  location: class Main
Main.java:12: error: cannot find symbol
			y2 = scan.nextDouble();
			^
  symbol:   variable y2
  location: class Main
Main.java:13: error: cannot find symbol
			x3 = scan.nextDouble();
			^
  symbol:   variable x3
  location: class Main
Main.java:14: error: cannot find symbol
			y3 = scan.nextDouble();
			^
  symbol:   variable y3
  location: class Main
Main.java:15: error: cannot find symbol
			xp = scan.nextDouble();
			^
  symbol:   variable xp
  location: class Main
Main.java:16: error: cannot find symbol
			yp = scan.nextDouble();
			^
  symbol:   variable yp
  location: class Main
Main.java:17: error: cannot find symbol
			double S_pab = Math.abs((x1 - xp) * (y2 - yp) - (x2 - xp) * (y1 - yp));
			                         ^
  symbol:   variable x1
  location: class Main
Main.java:17: error: cannot find symbol
			double S_pab = Math.abs((x1 - xp) * (y2 - yp) - (x2 - xp) * (y1 - yp));
			                              ^
  symbol:   variable xp
  location: class Main
Main.java:17: error: cannot find symbol
			double S_pab = Math.abs((x1 - xp) * (y2 - yp) - (x2 - xp) * (y1 - yp));
			                                     ^
  symbol:   variable y2
  location: class Main
Main.java:17: error: cannot find symbol
			double S_pab = Math.abs((x1 - xp) * (y2 - yp) - (x2 - xp) * (y1 - yp));
			                                          ^
  symbol:   variable yp
  location: class Main
Main.java:17: error: cannot find symbol
			double S_pab = Math.abs((x1 - xp) * (y2 - yp) - (x2 - xp) * (y1 - yp));
			                                                 ^
  symbol:   variable x2
  location: class Main
Main.java:17: error: cannot find symbol
			double S_pab = Math.abs((x1 - xp) * (y2 - yp) - (x2 - xp) * (y1 - yp));
			                                                      ^
  symbol:   variable xp
  location: class Main
Main.java:17: error: cannot find symbol
			double S_pab = Math.abs((x1 - xp) * (y2 - yp) - (x2 - xp) * (y1 - yp));
			                                                             ^
  symbol:   variable y1
  location: class Main
Main.java:17: error: cannot find symbol
			double S_pab = Math.abs((x1 - xp) * (y2 - yp) - (x2 - xp) * (y1 - yp));
			                                                                  ^
  symbol:   variable yp
  location: class Main
Main.java:18: error: cannot find symbol
			double S_pac = Math.abs((x1 - xp) * (y3 - yp) - (x3 - xp) * (y1 - yp));
			                         ^
  symbol:   variable x1
  location: class Main
Main.java:18: error: cannot find symbol
			double S_pac = Math.abs((x1 - xp) * (y3 - yp) - (x3 - xp) * (y1 - yp));
			                              ^
  symbol:   variable xp
  location: class Main
Main.java:18: error: cannot find symbol
			double S_pac = Math.abs((x1 - xp) * (y3 - yp) - (x3 - xp) * (y1 - yp));
			                                     ^
  symbol:   variable y3
  location: class Main
Main.java:18: error: cannot find symbol
			double S_pac = Math.abs((x1 - xp) * (y3 - yp) - (x3 - xp) * (y1 - yp));
			                                          ^
  symbol:   variable yp
  location: class Main
Main.java:18: error: cannot find symbol
			double S_pac = Math.abs((x1 - xp) * (y3 - yp) - (x3 - xp) * (y1 - yp));
			                                                 ^
  symbol:   variable x3
  location: class Main
Main.java:18: error: cannot find symbol
			double S_pac = Math.abs((x1 - xp) * (y3 - yp) - (x3 - xp) * (y1 - yp));
			                                                      ^
  symbol:   variable xp
  location: class Main
Main.java:18: error: cannot find symbol
			double S_pac = Math.abs((x1 - xp) * (y3 - yp) - (x3 - xp) * (y1 - yp));
			                                                             ^
  symbol:   variable y1
  location: class Main
Main.java:18: error: cannot find symbol
			double S_pac = Math.abs((x1 - xp) * (y3 - yp) - (x3 - xp) * (y1 - yp));
			                                                                  ^
  symbol:   variable yp
  location: class Main
Main.java:19: error: cannot find symbol
			double S_pbc = Math.abs((x2 - xp) * (y3 - yp) - (x3 - xp) * (y2 - yp));
			                         ^
  symbol:   variable x2
  location: class Main
Main.java:19: error: cannot find symbol
			double S_pbc = Math.abs((x2 - xp) * (y3 - yp) - (x3 - xp) * (y2 - yp));
			                              ^
  symbol:   variable xp
  location: class Main
Main.java:19: error: cannot find symbol
			double S_pbc = Math.abs((x2 - xp) * (y3 - yp) - (x3 - xp) * (y2 - yp));
			                                     ^
  symbol:   variable y3
  location: class Main
Main.java:19: error: cannot find symbol
			double S_pbc = Math.abs((x2 - xp) * (y3 - yp) - (x3 - xp) * (y2 - yp));
			                                          ^
  symbol:   variable yp
  location: class Main
Main.java:19: error: cannot find symbol
			double S_pbc = Math.abs((x2 - xp) * (y3 - yp) - (x3 - xp) * (y2 - yp));
			                                                 ^
  symbol:   variable x3
  location: class Main
Main.java:19: error: cannot find symbol
			double S_pbc = Math.abs((x2 - xp) * (y3 - yp) - (x3 - xp) * (y2 - yp));
			                                                      ^
  symbol:   variable xp
  location: class Main
Main.java:19: error: cannot find symbol
			double S_pbc = Math.abs((x2 - xp) * (y3 - yp) - (x3 - xp) * (y2 - yp));
			                                                             ^
  symbol:   variable y2
  location: class Main
Main.java:19: error: cannot find symbol
			double S_pbc = Math.abs((x2 - xp) * (y3 - yp) - (x3 - xp) * (y2 - yp));
			                                                                  ^
  symbol:   variable yp
  location: class Main
Main.java:20: error: cannot find symbol
			double S_abc = Math.abs((x3 - x1) * (y2 - y1) - (x2 - x1) * (y3 - y1));
			                         ^
  symbol:   variable x3
  location: class Main
Main.java:20: error: cannot find symbol
			double S_abc = Math.abs((x3 - x1) * (y2 - y1) - (x2 - x1) * (y3 - y1));
			                              ^
  symbol:   variable x1
  location: class Main
Main.java:20: error: cannot find symbol
			double S_abc = Math.abs((x3 - x1) * (y2 - y1) - (x2 - x1) * (y3 - y1));
			                                     ^
  symbol:   variable y2
  location: class Main
Main.java:20: error: cannot find symbol
			double S_abc = Math.abs((x3 - x1) * (y2 - y1) - (x2 - x1) * (y3 - y1));
			                                          ^
  symbol:   variable y1
  location: class Main
Main.java:20: error: cannot find symbol
			double S_abc = Math.abs((x3 - x1) * (y2 - y1) - (x2 - x1) * (y3 - y1));
			                                                 ^
  symbol:   variable x2
  location: class Main
Main.java:20: error: cannot find symbol
			double S_abc = Math.abs((x3 - x1) * (y2 - y1) - (x2 - x1) * (y3 - y1));
			                                                      ^
  symbol:   variable x1
  location: class Main
Main.java:20: error: cannot find symbol
			double S_abc = Math.abs((x3 - x1) * (y2 - y1) - (x2 - x1) * (y3 - y1));
			                                                             ^
  symbol:   variable y3
  location: class Main
Main.java:20: error: cannot find symbol
			double S_abc = Math.abs((x3 - x1) * (y2 - y1) - (x2 - x1) * (y3 - y1));
			                                                                  ^
  symbol:   variable y1
  location: class Main
40 errors