/*
 * Example of C structures
 */
struct point {
	double x;
	double y;
};

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

double distance( struct point a1, struct point a2);

double distance( struct point a1, struct point a2)
{
    return sqrt( pow(a1.x - a2.x, 2.) + pow(a1.y - a2.y, 2.) );
}

int main(void)
{
    struct point a = {0.,  0.}, b = {3., 4.};

    printf("%f\n", distance(a, b));

    return 0;
}