Searching 1-D Arrays

Find the smallest value in an array

int find_small(int array[], int low, int high)
{
  int small, index;

  small =  array[low];

  for (index = low + 1; index <= high; index++)
  {
     if (array[index] < small)
        small = array[index];
  }
  return small;
}

Find the location of a specified value in an array

int find_value_location(int array[], int low, int high, int value)
{
   int location, found, index;

   location = low - 1;
   found = 0;  /*0 stands for false in C*/
   index = low;
   while ((index  <= high) && (found == 0))
   {
      if (array[index] == value)
      {
         location = index;
         found = 1;
      }
      index = index + 1;
   }
   return location;
}

Recursive Binary Search to find the location of a specified value

 
/* binary search of an array to find a location.  Array must be in ascending
   order. 
   C has a function in stdlib.h called bsearch which is a generic binary
   search on a 1-d array. To use bsearch() you have to pass a function as
   a parameter to the subprogram.  This is also true of qsort(), which is
   a C quicksort subprogram.
*/

int binary_search(int array[], int low, int high, int value)
{
   int middle = (high - low)/2;
   int location;

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

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

main() function to test the above searches

int main(void)
{
   int arr1[10] = {3, 5, 2, 9, 3, 6, 4};
   int arr2[10] = {1, 3, 4, 5, 6, 7, 8};
   int small, location;

   small = find_small(arr1, 0, 6);
   printf("\nSmall = %d", small);
   location = find_value_location(arr1, 0, 6, small);
   printf("\nlocation = %d", location);
   location = binary_search(arr2, 0, 6, 4);
   printf("\nlocation = %d", location);

   return (0);
}