hdu2051

 #include<stdio.h>

 int main()
 {
     int n;
     int a[11];
     int len;
     while(~scanf("%d",&n))
     {
         len = 0;
         while(n!=0)
         {
             if(n%2==0)
             a[len++] = 0;
             else 
             a[len++] = 1;
             n /= 2;
         }
         while(len--)
         printf("%d",a[len]);
         
         printf("
");
        
     }
     return 0;
 }

说明：

1. 求二进制