15个数按从大到小的顺序存放在一个数组中。输入一个数，要求用折半查找法找出该数
在程序最后  为什么程序跳过输入N/Y 而直接执行 input number to look for?

下面是程序
#include<stdio.h>
#define N 15
void main()
{int i,number,top,bott,mid,loca,a[N],flag=1,sign;
char c;
printf("enter the data:\n");
scanf("%d",&a[0]);
i=1;
  while(i<N)
  {
      scanf("%d",&a[i]);
      if(a[i]>=a[i-1])
          i++;
      else
          printf("enter the data again:\n");
  }
printf("\n");
for(i=0;i<N;i++)
printf("%d ",a[i]);
printf("\n");
  while(flag)//flag为开关变量，控制程序是否结束运行
  {
      printf("input number to look for:");
      scanf("%d",&number);
      sign=0;
      top=0;
      bott=N-1;
      if((number<a[0])||number>a[i-1])
          loca=-1;
      while((!sign)&&(top<=bott))
      {
          mid=(top+bott)/2;
          if(number==a[mid])
          {
              loca=mid;
              printf("has found %d,its position is %d\n",number,loca+1);
              sign=1;
          }
      else if(number<a[mid])
          bott=mid-1;
      else
          top=mid+1;
      }
      if(!sign||loca==-1)
          printf("can't find %d.\n",number);
    printf("continue or not(Y/N)?");
    scanf("%c",&c);//这儿把输入格式的%c 误写成%d有影响吗
       if(c=='N'||c=='n')
          flag=0;
  }
}