Compilare: main.c: In function 'main': main.c:49:9: warning: ignoring return value of 'fscanf', declared with attribute warn_unused_result [-Wunused-result] fscanf(in, "%u", &n); ^~~~~~~~~~~~~~~~~~~~ main.c:55:21: warning: ignoring return value of 'fscanf', declared with attribute warn_unused_result [-Wunused-result] fscanf(in, "%u", &a[i][j]); ^~~~~~~~~~~~~~~~~~~~~~~~~~ main.c:82:13: warning: 'mj' may be used uninitialized in this function [-Wmaybe-uninitialized] drum(mi, mj, out); ^~~~~~~~~~~~~~~~~ main.c:82:13: warning: 'mi' may be used uninitialized in this function [-Wmaybe-uninitialized]