无符号长整型数据转换成二进制输出: void printBin(unsigned long int num) { int cnt = 0; unsigned mask = 1u<<31; for(; mask; mask>>=1) { if(cnt%8==0&&cnt!=0) cout<<" "; cout<< (num&mask?1:0); cnt++; } cout<<endl; } 无符号长整型数据最高字节和最低字节互换: