Compilare: main.cpp: In function 'std::vector<int> operator+(std::vector<int>, int)': main.cpp:43:25: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] while ( r != 0 && i < x.size ( ) ){ ~~^~~~~~~~~~~~ main.cpp: In function 'std::vector<int> operator-(std::vector<int>, std::vector<int>)': main.cpp:59:20: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for ( i = 0; i < x.size ( ); i++ ){ ~~^~~~~~~~~~~~ main.cpp:60:16: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] if ( i < y.size ( ) ){ ~~^~~~~~~~~~~~