Compilare: main.cpp: In member function 'void Heap::pushDown(int)': main.cpp:69:16: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] if (left >= data_.size()) ~~~~~^~~~~~~~~~~~~~~ main.cpp:73:17: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] if (right >= data_.size()) ~~~~~~^~~~~~~~~~~~~~~ main.cpp: In function 'int main()': main.cpp:105:36: 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); ^ main.cpp:109:18: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result [-Wunused-result] scanf("%d", &N); ^ main.cpp:114:21: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result [-Wunused-result] scanf("%d", &op); ^ main.cpp:117:22: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result [-Wunused-result] scanf("%d", &x); ^ main.cpp:122:22: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result [-Wunused-result] scanf("%d", &x); ^