Compilare: user.cpp: In function ‘int main()’: user.cpp:28:46: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] while(str[pos] != *it and pos < str.size()) ^ user.cpp:30:24: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] if(pos == str.size()) { ^ user.cpp:47:48: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] while(str[pos] != *it and pos < str.size()) ^