// typedef da otro nombre a un tipo. No crea un tipo distinto.
#include <stdio.h>

typedef int Meters;
typedef int Seconds;

double speed(Meters distance, Seconds time) {
    return (double) distance / time;
}

int main(void) {
    Meters distance = 1000;
    Seconds time = 50;

    printf("bien: %.2f m/s\n", speed(distance, time));
    printf("al revés: %.2f m/s\n", speed(time, distance));
    return 0;
}