c code

typedef struct {
    int x;
    int y;
} vertex;

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

void input(vertex *v) {
    printf("\nEnter x-coordinate: ");
    scanf("%d", &(v->x));
    printf("\nEnter y-coordinate: ");
    scanf("%d", &(v->y));

    return;
}

double distance(vertex a, vertex b) {
    double distance;
    double x_diff = a.x - b.x;
    double y_diff = a.y - b.y;

    distance = sqrt( (x_diff * x_diff) + (y_diff * y_diff));
    return distance;
}

int main() {
    vertex a, b, c;
    int temp = 1, flag= 0;
    double d1, d2, d3;

    while(true) {
        printf("\nEnter 1st vertex");
        input(&a);
        printf("\nEnter 2nd vertex");
        input(&b);
        printf("\nEnter 3rd vertex");
        input(&c);

        d1 = distance(a, b);
        d2 = distance(b, c);
        d3 = distance(c, a);

        if ( ((d1*d1) + (d2*d2)) == (d3*d3) ) flag = 1;
        if ( ((d3*d3) + (d2*d2)) == (d1*d1) ) flag = 1;
        if ( ((d1*d1) + (d3*d3)) == (d2*d2) ) flag = 1;

        if (flag == 1) printf ("\n\nThe vertices you entered belong to a right angled triangle.\n");
        else printf ("\n\nThe vertices you entered do not belong to a right angled triangle.\n");

        printf("Enter 1 to continue or 0 to exit: ");
        scanf("%d", &temp);

        if (temp == 0) break;
    }

    printf("\nThanks for using program.\n\n");
    return 0;
}