#include <stdio.h>
#include <stdlib.h>

int main(int argc, char *argv[]) {
    if (argc != 3) {
        fputs("Usage: ./a.out <valeur> <unité>\n",stderr);
        return EXIT_FAILURE;
    }

    double valeur = atof(argv[1]);
    char unite = argv[2][0];

    if (unite == 'c' || unite == 'C') {
        double pouces = valeur / 2.54;
        printf("%.2fin\n", pouces);
    } else if (unite == 'i' || unite == 'I') {
        double centimetres = valeur * 2.54;
        printf("%.2fcm\n", centimetres);
    } else {
        printf("Unité invalide. Utilisez 'cm' ou 'in'.\n");
        return EXIT_FAILURE;
    }

    return EXIT_SUCCESS;
}