Compilare: user.cpp: In function ‘int main()’: user.cpp:15:27: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for(int i=1; i<s.size(); i++){ ^ user.cpp:18:20: warning: ‘ok’ may be used uninitialized in this function [-Wmaybe-uninitialized] else if(ok && ((s[i-1]>='a' && s[i]<='z') || (s[i]>='A' && s[i]<='Z'))) ^