Compilare: user.cpp: In function ‘int main()’: user.cpp:33:36: warning: ignoring return value of ‘FILE* freopen(const char*, const char*, FILE*)’, declared with attribute warn_unused_result [-Wunused-result] freopen("heapuri.in","r",stdin); ^ user.cpp:34:38: warning: ignoring return value of ‘FILE* freopen(const char*, const char*, FILE*)’, declared with attribute warn_unused_result [-Wunused-result] freopen("heapuri.out","w",stdout); ^ user.cpp:35:20: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] scanf("%d", &n); ^ user.cpp:38:25: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] scanf("%d", &op); if (op<3) scanf("%d", &x); ^ user.cpp:38:52: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] scanf("%d", &op); if (op<3) scanf("%d", &x); ^ user.cpp: In function ‘void heap_down(int)’: user.cpp:19:44: warning: ‘son’ may be used uninitialized in this function [-Wmaybe-uninitialized] else {if (heap[2*poz].f<=heap[2*son+1].f) son=2*poz; else son=2*poz+1;} ^