Compilare: user.cpp: In function ‘int main()’: user.cpp:21:10: warning: unused variable ‘sf’ [-Wunused-variable] for(int sf=-1,i=0;i<8;i++){add(sx,sy,i,1);} ^ user.cpp:11:29: warning: ignoring return value of ‘FILE* freopen(const char*, const char*, FILE*)’, declared with attribute warn_unused_result [-Wunused-result] freopen("car.in","r",stdin); ^ user.cpp:12:31: warning: ignoring return value of ‘FILE* freopen(const char*, const char*, FILE*)’, declared with attribute warn_unused_result [-Wunused-result] freopen("car.out","w",stdout); ^ user.cpp:13:21: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] scanf("%d%d",&n,&m); ^ user.cpp:14:35: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] scanf("%d%d%d%d",&sx,&sy,&fx,&fy); ^ user.cpp:19:45: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] for(int j=1;j<=m;++j){scanf("%d",&v[i][j]);} ^