#include <stdio.h>

/**
 *
 * Exercise 3-1.  Write a version of the following binary 
 * search with only one test inside the loop and measure 
 * the difference in run-time.
 * 
 * int binsearch(int x, int v[], int n)
 * {
 *    int low, high, mid;
 *    
 *    low = 0;
 *    high = n - 1;
 *    while (low <= high) {
 *       mid = (low+high) / 2;
 *       if (x < v[mid])
 *          high = mid - 1;
 *       else if (x > v[mid])
 *          low = mid + 1;
 *       else    
 *          return mid;
 *    }
 *    return -1;
 * }
 */

int binsearch(int x, int v[], int n)
{
   int low, high, mid;

   low  = 0;
   high = n-1;
   mid  = (low+high)/2;

   while(x != v[mid] && low <= high) {
      if( x < v[mid] )
         high = mid - 1;
      else
         low = mid + 1;
      mid = (low+high)/2;
   } 

   return (x==v[mid]) ? mid : -1;
}