Compilare: user.cpp: In function ‘int main()’: user.cpp:31:45: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for (j = 0; j < v[poz].size(); ++j) ^ user.cpp:41:43: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for (j = 0; j < v[i].size(); ++j) ^ user.cpp:21:41: warning: ignoring return value of ‘FILE* freopen(const char*, const char*, FILE*)’, declared with attribute warn_unused_result [-Wunused-result] freopen("muzica.in", "r", stdin); ^ user.cpp:22:43: warning: ignoring return value of ‘FILE* freopen(const char*, const char*, FILE*)’, declared with attribute warn_unused_result [-Wunused-result] freopen("muzica.out", "w", stdout); ^ user.cpp:23:31: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] scanf ("%d%d", &N, &M); ^ user.cpp:24:49: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] scanf ("%d%d%d%d%d", &A, &B, &C, &D, &E); ^ user.cpp:26:32: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] scanf("%d", &x); ^