Write a function to compute the distance between two points and use it to develop another function that will compute the area of the triangle whose vertices are A(x1, y1), B(x2, y2), and C(x3, y3). Use these functions to develop a function which returns a value 1 if the point (x, y) lines inside the triangle ABC, otherwise a value 0.

#include<stdio.h>
#include<conio.h>
#include<math.h>

float dis(int, int, int, int);
float ar(int, int, int, int, int, int);
int main()
{
	int x1, x2, x3, y1, y2, y3, x, y;
	float A1, A2, A3, A;
	printf("Enter the cordinates of first point of the trianlge : ");
	scanf("%d%d", &x1, &y1);
	printf("\n\nEnter the cordinates of second point of the trianlge : ");
	scanf("%d%d", &x2, &y2);
	printf("\n\nEnter the cordinates of third point of the trianlge : ");
	scanf("%d%d", &x3, &y3);
	printf("\n\nEnter the points to check it's position : ");
	scanf("%d%d", &x, &y);
	A1 = ar(x1, y1, x2, y2, x, y);
	printf("A1 : %f\n", A1);
	A2 = ar(x1, y1, x3, y3, x, y);
	printf("A2 : %f\n", A2);
	A3 = ar(x, y, x2, y2, x3, y3);
	printf("A3 : %f\n", A3);
	A = ar(x1, y1, x2, y2, x3, y3);
	printf("A : %f\n", A);
	if (!(A1 + A2 + A3>A || A1 + A2 + A3<A))
		printf("\n\nThe point (%d,%d) lies inside of triangle.", x, y);
	else
		printf("\n\nThe point (%d,%d) lies outside of triangle.", x, y);
	getch();
	return 0;
}

float dis(int x1, int y1, int x2, int y2)
{
	float distance;
	distance = sqrt(pow((x2 - x1), 2) + pow((y2 - y1), 2));
	return (distance);
}

float ar(int x1, int y1, int x2, int y2, int x3, int y3)
{
	float a, b, c, area, S;
	a = dis(x1, y1, x2, y2);
	b = dis(x1, y1, x3, y3);
	c = dis(x2, y2, x3, y3);
	S = (a + b + c) / 2;
	area = sqrt(S*(S - a)*(S - b)*(S - c));
	return (area);
}