Compilare: main.cpp: In function 'int main()': main.cpp:9:33: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)', declared with attribute warn_unused_result [-Wunused-result] freopen("pipe.in","r",stdin); ^ main.cpp:10:35: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)', declared with attribute warn_unused_result [-Wunused-result] freopen("pipe.out","w",stdout); ^ main.cpp:13:49: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result [-Wunused-result] scanf("%d%d%d%d%d%c",&n,&xi,&yi,&xf,&yf,&ch); ^ main.cpp:20:31: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result [-Wunused-result] scanf("%c%d",&ch,&len); ^ main.cpp:27:24: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result [-Wunused-result] scanf("%c",&ch); ^