#include <stdio.h>
#include <stdlib.h>

struct point{
	float x;
	float y;
};

point *arrayofpoints;
point dot;


point *loadthis(const char*filename, int countofpoints);
void checkthis(int countofpoints);

int main(){
	int countofpoints = 0;
	printf("Enter the number of vertices : ");
	scanf("%d", &countofpoints);
	arrayofpoints = (point *)malloc(countofpoints * sizeof(point));
	if (countofpoints >= 3){
		arrayofpoints = (point *)malloc(countofpoints * sizeof(point));
		loadthis("ourfigure.txt", countofpoints);
		printf("Enter the top of which we will seek (x y): ");
		scanf("%f %f", &dot.x, &dot.y);
		checkthis(countofpoints);
		free(arrayofpoints);
	}
	else
		printf("Enter 3 or more vertices\n");
	return 0;
}

point *loadthis(const char*filename, int countofpoints){
	FILE *input = fopen(filename, "r");
	if (input == NULL){
		printf("Cannot open input file \n");
		exit(0);
	}
	else{
		for (int i = 0; i < countofpoints; i++){
			fscanf(input, "%f %f", &arrayofpoints[i].x, &arrayofpoints[i].y);
		}
		printf("Our points : \n");
		printf("Number     x  y \n");
		for (int i = 0; i < countofpoints; i++){
			printf("point[%d] : %f  %f\n", i, arrayofpoints[i].x, arrayofpoints[i].y);
		}
	}
	return arrayofpoints;
}

void checkthis(int countofpoints){
	bool result = false;
	int j = countofpoints - 1;
	//check dot in figure
	for (int i = 0; i < countofpoints; i++) {
		if ((arrayofpoints[i].y < dot.y && arrayofpoints[j].y >= dot.y || arrayofpoints[j].y < dot.y && arrayofpoints[i].y >= dot.y) &&
			(arrayofpoints[i].x + (dot.y - arrayofpoints[i].y) / (arrayofpoints[j].y - arrayofpoints[i].y) * (arrayofpoints[j].x - arrayofpoints[i].x) < dot.x))
			result = true;
		j = i;
	}
	//check dot in dot
	if (result == false)
	for (int i = 0; i < countofpoints; i++){
		if (arrayofpoints[i].y == dot.y && arrayofpoints[i].x == dot.x)
			result = true;
	}
	//check dot in line
	if (result == false)
	for (int i = 0; i < countofpoints - 1; i++){
		if (((dot.y - arrayofpoints[i].y) / (arrayofpoints[i + 1].y - arrayofpoints[i].y)) == ((dot.x - arrayofpoints[i].x) / (arrayofpoints[i + 1].x - arrayofpoints[i].x)))
			result = true;
	}
	if (result == false)
		printf("No");
	else printf("Yes");
}