Compilare: user.cpp: In function ‘bool check()’: user.cpp:19:26: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for (int i = 0 ; i < n ; i++) ^ user.cpp:20:34: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for (int j = i + 1 ; j < n ; j ++) ^ user.cpp:21:37: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for (int k = j + 1 ; k < n ; k++) ^ user.cpp: In function ‘int main()’: user.cpp:30:25: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for (int i = 0; i < n; i++) ^ user.cpp:35:26: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for (int i = 2 ; i < k ; i++){ ^ user.cpp:42:26: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for (int i = n ; i < k ; i++) ^ user.cpp:44:26: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for (int i = 0 ; i < k; i++) ^