Compilare: user.cpp: In function ‘int main()’: user.cpp:79:34: warning: ignoring return value of ‘FILE* freopen(const char*, const char*, FILE*)’, declared with attribute warn_unused_result [-Wunused-result] freopen("fence.in","r",stdin); ^ user.cpp:80:36: warning: ignoring return value of ‘FILE* freopen(const char*, const char*, FILE*)’, declared with attribute warn_unused_result [-Wunused-result] freopen("fence.out","w",stdout); ^ user.cpp:82:19: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] scanf("%d",&t); ^ user.cpp:83:57: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] scanf("%d%d%d%d%d%d%d",&n,&m,&v,&xx1,&xx2,&yy1,&yy2); ^ user.cpp:86:33: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] scanf("%d",&a[i][j]); ^