Compilare: user.cpp: In function ‘int main()’: user.cpp:24:34: 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, 20000, stdin); ^ user.cpp:37:28: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] scanf("%d%d",&x,&y); ^ user.cpp: In function ‘void read(int&)’: user.cpp:12:103: 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 == 20000) fread(buff, 1, 20000, stdin), pos = 0; ^ user.cpp:17:65: warning: ignoring return value of ‘size_t fread(void*, size_t, size_t, FILE*)’, declared with attribute warn_unused_result [-Wunused-result] if(++pos == 20000) fread(buff, 1, 20000, stdin), pos = 0; ^