Compilare: user.cpp: In function ‘int main()’: user.cpp:19:37: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for (i=0;i<=b.length()-a.length();i++) ^ user.cpp:23:29: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for (j=0;j<a.length();j++) ^ user.cpp:38:24: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for (i=0;i<ap.size();i++) g << ap[i] << " "; ^