Compilare: user.cpp: In function ‘int main()’: user.cpp:30:27: warning: ignoring return value of ‘size_t fread(void*, size_t, size_t, FILE*)’, declared with attribute warn_unused_result [-Wunused-result] {fread(buff,1,buffs,stdin); ^ user.cpp:31:30: warning: ignoring return value of ‘FILE* freopen(const char*, const char*, FILE*)’, declared with attribute warn_unused_result [-Wunused-result] freopen("dfs.out","w",stdout); ^ user.cpp: In function ‘void read(int&)’: user.cpp:14:84: warning: ignoring return value of ‘size_t fread(void*, size_t, size_t, FILE*)’, declared with attribute warn_unused_result [-Wunused-result] while(buff[pos]<'0'||buff[pos]>'9') if(++pos==buffs)fread(buff,1,buffs,stdin),pos=0; ^ user.cpp:18:52: warning: ignoring return value of ‘size_t fread(void*, size_t, size_t, FILE*)’, declared with attribute warn_unused_result [-Wunused-result] if(++pos==buffs)fread(buff,1,buffs,stdin),pos=0; ^