Compilare: user.cpp: In function ‘int main()’: user.cpp:67:34: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for( int i = 1; i < plg.size(); i ++ ) { ^ user.cpp:77:43: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for( int j = 0; j < lst2.size(); j ++ ) { ^ user.cpp:84:35: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for( int i = 0; i < lst1.size(); i ++ ) ^ user.cpp:86:35: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for( int i = 0; i < lst2.size(); i ++ ) ^