Compilare: user.cpp: In function ‘int main()’: user.cpp:75:37: warning: ignoring return value of ‘FILE* freopen(const char*, const char*, FILE*)’, declared with attribute warn_unused_result [-Wunused-result] freopen("demolish.in","r",stdin); ^ user.cpp:76:39: warning: ignoring return value of ‘FILE* freopen(const char*, const char*, FILE*)’, declared with attribute warn_unused_result [-Wunused-result] freopen("demolish.out","w",stdout); ^ user.cpp:83:41: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] scanf("%d%d%d%d%d",&n,&m,&f,&dx,&dy); ^ user.cpp:86:78: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] scanf("%d%d%d%d%d",&ve[i].xs,&ve[i].ys,&ve[i].xf,&ve[i].yf,&ve[i].co); ^