Compilare: main.cpp: In function 'int main()': main.cpp:47:32: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)', declared with attribute warn_unused_result [-Wunused-result] freopen("vis.in","r",stdin); ^ main.cpp:48:34: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)', declared with attribute warn_unused_result [-Wunused-result] freopen("vis.out","w",stdout); ^ main.cpp:50:62: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result [-Wunused-result] scanf("%d%d%d%d%d%d%d", &n, &k1, &k2, &l1, &c1, &l2, &c2); ^ main.cpp:53:36: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result [-Wunused-result] scanf("%d", &mat[i][j]); ^