Compilare: user.cpp: In function ‘int main()’: user.cpp:14:23: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for(i=0; i<s.size(); i++) ^ user.cpp:18:23: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for(i=0; i<s.size(); i++) ^ user.cpp:29:46: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] if(f[k]>(s.size()-i)/2) ^ user.cpp:42:46: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] if(f[k]>(s.size()-i)/2) ^ user.cpp:24:15: warning: suggest explicit braces to avoid ambiguous ‘else’ [-Wparentheses] if(f[j]>0) ^