Compilare: user.cpp: In function ‘void scan()’: user.cpp:56:26: warning: ignoring return value of ‘FILE* freopen(const char*, const char*, FILE*)’, declared with attribute warn_unused_result [-Wunused-result] freopen(IN,"r",stdin); ^ user.cpp:57:28: warning: ignoring return value of ‘FILE* freopen(const char*, const char*, FILE*)’, declared with attribute warn_unused_result [-Wunused-result] freopen(OUT,"w",stdout); ^ user.cpp:59:29: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] scanf("%d%d%d",&X,&Y,&Z); ^ user.cpp:60:32: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] FOR(i,1,X) scanf("%d",S1+i); ^ user.cpp:61:32: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] FOR(i,1,Y) scanf("%d",S2+i); ^ user.cpp:62:32: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] FOR(i,1,Z) scanf("%d",S3+i); ^