Compilare: main.cpp: In function 'int main()': main.cpp:11:40: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)', declared with attribute warn_unused_result [-Wunused-result] freopen ("derdelus.in", "r", stdin); ^ main.cpp:12:42: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)', declared with attribute warn_unused_result [-Wunused-result] freopen ("derdelus.out", "w", stdout); ^ main.cpp:16:33: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result [-Wunused-result] scanf ("%d%d%d", &n, &m, &q); ^ main.cpp:19:35: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result [-Wunused-result] scanf ("%d%d", &lin, &col); ^