Compilare: user.cpp: In function ‘int main()’: user.cpp:9:36: warning: ignoring return value of ‘FILE* freopen(const char*, const char*, FILE*)’, declared with attribute warn_unused_result [-Wunused-result] freopen("dunarea.in", "r", stdin); ^ user.cpp:10:38: warning: ignoring return value of ‘FILE* freopen(const char*, const char*, FILE*)’, declared with attribute warn_unused_result [-Wunused-result] freopen("dunarea.out", "w", stdout); ^ user.cpp:12:32: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] scanf("%d %d %d", &A, &B, &N); ^ user.cpp:14:46: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] scanf("%d %d", &v[i].first, &v[i].second); ^ user.cpp:17:14: warning: ‘dr’ may be used uninitialized in this function [-Wmaybe-uninitialized] int k, st, dr, i; ^ user.cpp:29:5: warning: ‘st’ may be used uninitialized in this function [-Wmaybe-uninitialized] if(v[i].first > st and v[i].second > dr) { ^