Compilare: main.c: In function 'main': main.c:11:2: warning: ignoring return value of 'freopen', declared with attribute warn_unused_result [-Wunused-result] freopen("custi.in", "r", stdin); ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ main.c:12:2: warning: ignoring return value of 'freopen', declared with attribute warn_unused_result [-Wunused-result] freopen("custi.out", "w", stdout); ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ main.c:14:2: warning: ignoring return value of 'scanf', declared with attribute warn_unused_result [-Wunused-result] scanf("%d", &n); ^~~~~~~~~~~~~~~ main.c:17:4: warning: ignoring return value of 'scanf', declared with attribute warn_unused_result [-Wunused-result] scanf("%d", &matrix[i][j]); ^~~~~~~~~~~~~~~~~~~~~~~~~~