Compilare: user.cpp: In function ‘int main()’: user.cpp:52:35: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for (int k = 0; k < v1.size(); ++k) { ^ user.cpp:65:35: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for (int k = 0; k < v2.size(); ++k) { ^ user.cpp:13:37: warning: ignoring return value of ‘FILE* freopen(const char*, const char*, FILE*)’, declared with attribute warn_unused_result [-Wunused-result] freopen ("palind2.in", "r", stdin); ^ user.cpp:14:39: warning: ignoring return value of ‘FILE* freopen(const char*, const char*, FILE*)’, declared with attribute warn_unused_result [-Wunused-result] freopen ("palind2.out", "w", stdout); ^ user.cpp:17:19: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] scanf ("%d", &T); ^ user.cpp:20:21: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] scanf ("%d", &N); ^ user.cpp:27:23: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] scanf ("%d", &x); ^ user.cpp:84:52: warning: ‘nr2’ may be used uninitialized in this function [-Wmaybe-uninitialized] printf ("%d %d\n", min_op1 + min_op2, nr1 * nr2); ^ user.cpp:84:52: warning: ‘nr1’ may be used uninitialized in this function [-Wmaybe-uninitialized]