Question

The elements of an integer-valued array can be initialized so that a[i] == i in a recursive fashion as follows: An array of size 0 is already initialized; Otherwise set the last element of the array to n-1 (where n is the number of elements in the array, for example, an array of size 3 will have its last element -- index 2-- set to 2; and initialize the portion of the array consisting of the first n-1 elements (i.e., the other elements of the array) Write a void method named init that accepts an integer array, and the number of elements in the array and recursively initializes the array so that a[i] == i.

Answer 1

The student asked for a recursive method to initialize an array with each element set to its index. The 'init' method recursively sets the last element and calls itself with the sub-array of size 'n-1'. This involves concepts of arrays, recursion, and base cases in programming.

Step-by-step explanation:

The student is asking how to write a void method named init that recursively initializes an integer array so that each element at index i equates to the value of i itself (a[i] == i). This task falls within the domain of computer programming, specifically dealing with arrays and recursion in Java (or a similar language).

A possible implementation of the init method is as follows:

public static void init(int[] a, int n) {
if (n > 0) {
a[n-1] = n-1;
init(a, n-1);
}
}

This recursive logic bases on two conditions: the base case where the size of the array is zero (no action needed), and the recursive case where we set the last element of the array to its correct value and then call the function again with the 'n-1' sub-array.

Answer 2

public static void init(int[] arr, int n) {

if (n==0)

arr[0] = 0;

else {

arr[n-1] = n - 1;

init(arr, n-1);

}

}

Step-by-step explanation:

Create a method called init that takes two parameters, an array and the number of elements in the array

When n reaches 0, set the first element to 0 (This is a base for our recursive method)

Otherwise, set the element in index i to i

Call the init inside the init, this is the recursion part, with same array but decrease the number of elements by 1 (We decrease the number of element by 1 in each time so that it goes through all the elements in the array)