1 #include 
     
       2 void binary(int d){ 3  int i=0,j,n,b[8]={
   0};  4  while(d>0){ 5  n=d%2; 6  d=d/2; 7  b[i++]=n; //不停的除2，余数保存在b[8] 数组中 8  } 9 for(j=7;j>=0;j--)10  printf("%d",b[j]); //将余数倒序输出，即为所求。11  printf(" ");12 }13 14 void main()15 {16  int d1,d2,d3,d4;17  d1=d2=d3=d4=0;18  printf("input decimal ip address:\n");19  scanf("%d.%d.%d.%d",&d1,&d2,&d3,&d4);20  printf("%3d.%3d.%3d.%3d\n",d1,d2,d3,d4);21  printf("binary ip address:\n");22  binary(d1);23  binary(d2);24  binary(d3);25  binary(d4);26 }