#include<stdio.h>
#define N 7
main()
{int i,number,top,mid,bott,loca,a[N],flag=1,sign;
char c;
printf("enter 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 this data again:\n");}
    }
printf("\n");
for(i=0;i<N;i++)
{printf("%4d",a[i]);}
printf("\n");
while(flag)
    {printf("input number to look for  ");
    scanf("%d",&number);
    sign=0;
    top=0;
    bott=N-1;
    if(number<a[0]||number>a[N-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("cannot find %d.\n",number);
   
    printf("continue or not(Y/N)?");
    scanf("%c",&c);
    if(c=='N'||c=='n')
        flag=0;
    }
return 0;
}

我运行到这
printf("continue or not(Y/N)?");
scanf("%c",&c);
输出就变成continue or not(Y/N)?input number to look for  直接跳过scanf("%c",&c);了。

为什么 加个getchar（）；呢

虽然还是很茫然 但是多谢指点 ！我也会坚持学下去的！！

头都大了好深奥