數字顛倒

#include<stdio.h>
int main()
{
   int i,j;
   char b[12];
   while(~scanf("%s",b))
   {
       j=0;
       while(b[j]!='\0'){j++;}
       i=j-1;
       j=0;
       while(b[i]=='0'){i--;}
       while(b[j]=='0'){j++;}
       if(i<j)printf("0");
       else
       while(i>=j){printf("%c",b[i]);i--;}
       printf("\n");
   }
  return 0;
}