1 #include <stdio.h>
 2 #define MAX 1000
 3 
 4 //prototypes
 5 int BinarySearch(int a[],int high,int low);
 6 
 7 int main()
 8 {
 9     int x[MAX]={-2,2,4,7,8};//x[i]=i+1;
10     int low=0;
11     int high=4;
12     int result=BinarySearch(x,high,low);
13     printf("%d\n",x[result]);
14 }
15 
16 int BinarySearch(int a[],int high,int low)
17 {
18     while(low<=high)
19     {
20         int mid=low+(high-low)/2;
21         if(a[mid]==mid+1)
22             return mid;
23         else if(a[mid]>mid+1)
24             high=mid-1;
25         else 
26             low=mid+1;
27     }
28     return -1;
29 }