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

struct City
{
    int cityID;
    float x;
    float y;
};


float Distance(struct City A,struct City B)
{
    float distance;

    distance = sqrt(pow((B.x-A.x),2)+pow(B.y-A.y,2));

    return distance;
}


int main()
{
    /* //by user
    struct City city[3];

    int i;

    printf("\tinput\n");
    for(i=0;i<3;i++)
    {
        printf("%d ", i+1);
        scanf("%f %f", &city[i].x, &city[i].y);
        city[i].cityID = i+1;
    }

    printf("\toutput\n");
    for(i=0;i<3;i++)
    {
        printf("%d ", i+1);
        printf("%.2f %.2f\n", city[i].x, city[i].y);
    }

    printf("\t\t\t%.2f\n", Distance(city[0],city[2]));

    */

    //by initialize
    //test case1
    struct City city[] = {
        {1,0.0,0.0},
        {2,1.0,5.0},
        {3,3.0,4.0}
    };

    //test case2
    /*
    struct City city[] = {
        {1,13.794,100.323},
        {2,13.777,100.328},
        {3,13.789,100.277}
    };
    */

    int i;

    printf("\tinput\t\toutput\n");
    for(i=0;i<3;i++)
    {
        printf("%.1d %.1f\t%.1f\t\t%.2f\t%.2f\n",i+1,city[i].x,city[i].y,city[i].x,city[i].y);
    }

    printf("\t\t\t%.2f\n", Distance(city[0],city[2]));

    return 0;
}