Compilare: user.c: In function ‘main’: user.c:13:31: warning: implicit declaration of function ‘euclid’ [-Wimplicit-function-declaration] fprintf(fout, "%d\n", euclid(a, b)); ^~~~~~ user.c:10:5: warning: ignoring return value of ‘fscanf’, declared with attribute warn_unused_result [-Wunused-result] fscanf(fin, "%d", &n); ^~~~~~~~~~~~~~~~~~~~~ user.c:12:9: warning: ignoring return value of ‘fscanf’, declared with attribute warn_unused_result [-Wunused-result] fscanf(fin, "%d%d", &a, &b); ^~~~~~~~~~~~~~~~~~~~~~~~~~~