BINARY SEARCH

#include<stdio.h>

int main()

{

   int c, first, last, middle, n, search, array[100];

   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;

   middle = (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 present in the list.\n", search);

   return 0;  

}

Output:

Enter number of elements

5

Enter 5 integers

1

2

3

4

5

Enter value to find

3

3 found at location 3.