Compilare: user.cpp: In function ‘int main()’: user.cpp:22:29: warning: ignoring return value of ‘size_t fread(void*, size_t, size_t, FILE*)’, declared with attribute warn_unused_result [-Wunused-result] fread(buff,1,300000,stdin); ^ user.cpp: In function ‘void read(int&)’: user.cpp:10:105: 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 == 300000) fread(buff, 1, 300000, stdin), pos = 0; ^ user.cpp:15:67: warning: ignoring return value of ‘size_t fread(void*, size_t, size_t, FILE*)’, declared with attribute warn_unused_result [-Wunused-result] if(++pos == 300000) fread(buff, 1, 300000, stdin), pos = 0; ^