Binary search:

#include<stdio.h>

 void main()
{
   int   c, first, last, middle, n, search, array[25];

   printf("Enter number of elements\n");
   scanf("%d",&n);

   printf("Enter %d integers\n", n);

   for ( c = 0 ; c < n ; c++ )
      scanf("%d",&array[c]);

   printf("Enter value to find\n");
   scanf("%d",&search);

   first = 0;
   last = n - 1;
   center = (first+last)/2;

   while( first <= last )
   {
      if ( array[middle] < search )
         first = middle + 1;  
      else if ( array[middle] == search )
      {
         printf("%d  found at location %d.\n", search, middle+1);
         break;
      }
      else
         last = middle - 1;

      middle= (first + last)/2;
   }
   if ( first > last )
      printf("Not found! %d  is not existing in the record.\n", search);

   getch0;  
}