Compilare: main.c: In function 'main': main.c:26:5: warning: ignoring return value of 'freopen', declared with attribute warn_unused_result [-Wunused-result] freopen("marceland.in", "r", stdin); ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ main.c:27:5: warning: ignoring return value of 'freopen', declared with attribute warn_unused_result [-Wunused-result] freopen("marceland.out", "w", stdout); ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ main.c:30:10: warning: ignoring return value of 'scanf', declared with attribute warn_unused_result [-Wunused-result] for (scanf("%d", &t); t > 0; t--) { ^~~~~~~~~~~~~~~ main.c:32:9: warning: ignoring return value of 'scanf', declared with attribute warn_unused_result [-Wunused-result] scanf("%d%d", &n, &m); ^~~~~~~~~~~~~~~~~~~~~ main.c:34:13: warning: ignoring return value of 'scanf', declared with attribute warn_unused_result [-Wunused-result] scanf("%s", mat[i] + 1); ^~~~~~~~~~~~~~~~~~~~~~~