Compilare: user.cpp: In function ‘int main()’: user.cpp:14:36: warning: ignoring return value of ‘FILE* freopen(const char*, const char*, FILE*)’, declared with attribute warn_unused_result [-Wunused-result] freopen("betasah.in","r",stdin); ^ user.cpp:15:38: warning: ignoring return value of ‘FILE* freopen(const char*, const char*, FILE*)’, declared with attribute warn_unused_result [-Wunused-result] freopen("betasah.out","w",stdout); ^ user.cpp:16:33: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] scanf("%d%d%d", &n, &dm, &k); nr=0; ^ user.cpp:20:42: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] scanf("%d%d", &d[i][0], &d[i][1]); ^ user.cpp:25:46: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] for (i=1;i<=k;i++) {scanf("%d%d", &x, &y); a[x][y]=-1; v[x]--;} ^