Compilare: main.cpp: In member function 'void SegmentTree::cleannode(int, int, int)': main.cpp:81:11: warning: unused variable 'mid' [-Wunused-variable] int mid = (from + to) / 2; ^~~ main.cpp: In member function 'char InParser::read_ch()': main.cpp:19:29: warning: ignoring return value of 'size_t fread(void*, size_t, size_t, FILE*)', declared with attribute warn_unused_result [-Wunused-result] fread(buff, 1, 4096, fin); ^