Compilare: main.cpp: In function 'int main()': main.cpp:111:28: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for ( size_t i = 0 ; i < a ; ++ i , out << '\n' ) { ~~^~~ main.cpp:115:32: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for ( size_t j = 0 ; j < b ; ++ j ) out << ans[ i ][ j ] << ' ' ; ~~^~~ main.cpp: In member function 'char InParser::read_ch()': main.cpp:50:29: 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); ^