Compilare: user.cpp: In function ‘bool verifica(int)’: user.cpp:30:24: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] while (i<a.length()) ^ user.cpp:32:33: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] if ((x+i-1<=b.length()) && (a[i-1]!=b[x+i-2])) { q=false; break; } ^ user.cpp: In function ‘int main()’: user.cpp:42:31: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for (int i=1; i<=b.length(); i++) ^