Recursive Function to Count Occurrences of a Key in an Array

What is the purpose of the recursive function mentioned?

The recursive function is designed to count the occurrences of a given key in an array. It takes an array, its number of elements, and the search key as inputs. By recursively dividing the array into smaller subarrays, the function checks each element and increments a counter if the element matches the key. The function returns the total count of occurrences of the key in the array.

Explanation:

To count the occurrences of a key in an array recursively, we can use a divide-and-conquer approach. The recursive function takes three parameters: the array, the number of elements in the array, and the search key.

In the function, we check the base case where the number of elements in the array is zero. If the array is empty, we return zero as there are no occurrences of the key.

If the array is not empty, we compare the first element of the array with the search key. If they match, we increment a counter variable. Then, we make a recursive call to the function with the remaining elements of the array and add the result to the counter.

By repeatedly dividing the array into smaller subarrays and making recursive calls, we count the occurrences of the key throughout the entire array. Finally, we return the total count.

In the provided examples, the recursive function is called with different arrays and search keys. The function correctly counts the occurrences and returns the result. If the key is not found in the array, the function returns zero.

It's worth noting that the implementation of the recursive function is not provided in the question. The explanation above outlines the general approach for implementing such a function.