Compilare: user.cpp: In function ‘int main()’: user.cpp:17:30: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for(int i = 0; i<strlen(s); i++) ^ user.cpp:22:32: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for(int i = 0; i < strlen(s); i++) ^ user.cpp:23:34: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for(int j = i+1; j < strlen(s); j++) ^