(Linear Search) Modify the program in Fig. 6.15 to use recursive function linearSearch to perform a linear search of the array. The function should receive an integer array and the size of the array as arguments. If the search key is found, return the array subscript; otherwise, return –1.

Question

What will be an ideal response?

Answer 1

```
#include
using namespace std;

int linearSearch( const int [], int, int, int );

int main()
{
const int SIZE = 100;
int array[ SIZE ];
int searchKey;
int element;

// initialize array elements
for ( int loop = 0; loop < SIZE; loop++ )
array[ loop ] = 2 * loop;

// obtain search key from user
cout << "Enter the integer search key: ";
cin >> searchKey;

// search array for search key
element = linearSearch( array, searchKey, 0, SIZE - 1 );

// display if search key was found
if ( element != -1 )
cout << "Found value in element " << element << endl;
else
cout << "Value not found" << endl;
} // end main

// function to search array for specified key
int linearSearch( const int array[], int key, int low, int high )
{
// search array for key
if ( array[low] == key )
return low;
else if ( low == high )
return -1;
else
return linearSearch( array, key, low + 1, high );
} // end function linearSearch
```
Enter the integer search key: 18
Found value in element 9
Enter the integer search key: 17
Value not found