Compilare: user.cpp: In function ‘bool comp(std::string, std::string)’: user.cpp:16:48: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for(int i = 0 ; i < min(a.size() , b.size()) ; ++i) { ^ user.cpp: In function ‘int main()’: user.cpp:48:35: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] while(p < sir[i - 1].size() && p < sir[i].size() && sir[i - 1][p] == sir[i][p]) { ^ user.cpp:48:56: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] while(p < sir[i - 1].size() && p < sir[i].size() && sir[i - 1][p] == sir[i][p]) { ^