Searching 1-D ARRAYS

Searching Ordered 1-D Arrays

The following binary search will find the location of a specific value in a list of integers. NOTE: for binary search to work correctly, the list must be in order. In this example, I assume the list is in ascending order.

Recursive version

int find_location(int array[], int low, int high, int value)
{
   int middle;
   int location;

   if (low == high)
     middle = low;
   else
     middle = (high - low) / 2;

   if (low < high) 
     location = -1;
   else if (value < array[middle])
     location = find_location(array, low, middle - 1, value);
   else if (value > array[middle])
     location = find_location(array, middle + 1, high, value);
   else
     location = middle;  
   return(middle);
}

Iterative version

int find_location(int array[], int low, int high, int value)
{
   int temp_low = low, middle, temp_high = high;
   int found = 0;

   while ((temp_high - temp_low > 0) && (found == 0))
   {
     middle = (temp_low + temp_high) / 2;
     if (array[middle] == value)
       found = 1;
     else if (array[middle] < value)
       temp_low = middle - 1;
     else
       temp_high = middle  + 1;
   }
   if (found == 1 )
     return (middle);
   else
     return (low - 1);
}