int main() {
        int c[4];
        int ret;
        first_comb(6,4,c);
        printf("premiere combinaison: %d%d%d%d\n",c[0],c[1],c[2],c[3]);
        do {
                ret = next_comb_lex(6,4,c);
                printf("Next: %d%d%d%d\n",c[0],c[1],c[2],c[3]);
        } while(ret != 0);
        return 0;
}