Compilare: main.cpp: In function 'int main()': main.cpp:53:19: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for (int i = 0; i<s1.length(); ++i) ~^~~~~~~~~~~~ main.cpp:59:18: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for (int i=2; i<s1.length(); ++i) { ~^~~~~~~~~~~~ main.cpp:63:17: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] while (r<s1.length() && s1[r-i+1] == s1[r]) ++r; ~^~~~~~~~~~~~ main.cpp:71:18: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] while (r<s1.length() && s1[r-i+1] == s1[r]) {++r; ++z1[i];} ~^~~~~~~~~~~~