请看一下这个程序

#include<stdio.h>
#include<windows.h>
int main()
{
      int i,j=0,k=0;
      printf("enter a number:");
      scanf("%d",&i);
      
      while(i!=-1)
      {if(i>=j)
       {j=i;
       printf("enter a number:");
       scanf("%d",&i);}
          else if(i>=k)
         { k=i;
           printf("enter a number:");
           scanf("%d",&i);}
           else
           {printf("enter a number:");
            scanf("%d",&i);}}
       printf("the biggest is:%d\n",j);
       printf("the bigger is:%d\n",k);
       system("pause");
       return 0;}
这里第二大的值为什么算不出来呢