Compilare: user.cpp: In function ‘int main()’: user.cpp:5:32: warning: ignoring return value of ‘FILE* freopen(const char*, const char*, FILE*)’, declared with attribute warn_unused_result [-Wunused-result] freopen("nop.in","r",stdin); ^ user.cpp:6:34: warning: ignoring return value of ‘FILE* freopen(const char*, const char*, FILE*)’, declared with attribute warn_unused_result [-Wunused-result] freopen("nop.out","w",stdout); ^ user.cpp:9:19: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] scanf("%d",&t); ^ user.cpp:13:23: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] scanf("%d",&n); ^ user.cpp:29:13: warning: ‘ly’ may be used uninitialized in this function [-Wmaybe-uninitialized] for(j=1;j<=ly;j++) ^ user.cpp:27:9: warning: ‘lx’ may be used uninitialized in this function [-Wmaybe-uninitialized] for(i=1;i<=lx;i++) ^