Compilare: main.cpp: In function 'std::__cxx11::string unite(std::__cxx11::string, std::__cxx11::string)': main.cpp:24:18: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for(int i=0;i<=a.size();i++) ~^~~~~~~~~~ main.cpp:27:14: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] if(pb<b.size()) ~~^~~~~~~~~ main.cpp:31:22: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for(int j=i;j<a.size();j++) ~^~~~~~~~~ main.cpp:45:17: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] if(i<a.size()) ~^~~~~~~~~