Compilare: main.cpp:5:0: warning: ignoring #pragma GCC optimization [-Wunknown-pragmas] #pragma GCC optimization ("unroll-loops") main.cpp:6:0: warning: ignoring #pragma GCC optimization [-Wunknown-pragmas] #pragma GCC optimization("Ofast,O3,unroll-loops,no-stack-protector,fast-math") main.cpp: In member function 'char InParser::read_ch()': main.cpp:20:29: 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); ^