Точка

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

typedef struct tocka2D {
	double x;
	double y;
} tocka2D;

float rastojanie(tocka2D t1, tocka2D t2) {
	return sqrt ((t1.x - t2.x) * (t1.x - t2.x) + (t1.y - t2.y) * (t1.y - t2.y));
}

typedef struct tocka3D {
	float x;
    float y;
    float z;

} tocka3D ;

float rastojanie3D(tocka3D t1, tocka3D t2) {
	float d;
    d=sqrt((t2.x-t1.x)*(t2.x-t1.x) +(t2.y-t1.y)*(t2.y-t1.y) + (t2.z-t1.z)*(t2.z-t1.z));
    return d;

}

int ista_prava(tocka2D t1, tocka2D t2, tocka2D t3) {
    float k1,k2,k3;
    k1=(t2.y-t1.y)/(t2.x-t1.x);
	k2=(t3.y-t2.y)/(t3.x-t2.x);
    k1=(t3.y-t1.y)/(t3.x-t1.x);
    if(k1==k2==k3) return 0;
    else return 1;
}

int main() {
    float x1, y1, x2, y2;
    scanf("%f %f", &x1, &y1);
	scanf("%f %f", &x2, &y2);
	tocka2D t1 = { x1, y1 };
	tocka2D t2 = { x2, y2 };
	printf("%.2f\n", rastojanie(t1, t2));
    float z1, z2;
    scanf("%f %f", &z1, &z2);
    tocka3D t3 = {x1, y1, z1};
    tocka3D t4 = {x2, y2, z2};
    printf("%.2f\n", rastojanie3D(t3, t4));
    tocka2D t5 = {z1, z2};
    printf("%d\n", ista_prava(t1, t2, t5));
	return 0;
}