gistfile1.c

#include <stdio.h>

struct json_field {
    const char* field;
    int is_here;
};

int main(void)
{
    /* Met 0 ou 1 pour simuler l'absence/présence du champ */
    struct json_field fields[] = { { "'fsname': 'dev'", 1 },
                                   { "'percentage_used': '0.000000'", 1 },
                                   { "'mount_point': 'dev/'", 1 } };
    int nb_field = 0;
    size_t i;

    puts("{");
    for (i = 0; i < (sizeof fields/sizeof fields[0]); ++i) {
        if (fields[i].is_here) {
            if (nb_field != 0)
                puts(",");
            printf("\t%s", fields[i].field);
            nb_field++;
        }
    }
    puts("\n}");
    return 0;
}