Question

Write a program in C++ language that finds the largest number in an array of positive numbers using recursion. Your program should have a function called array_max that should pass in an int array, and an int for the size of the array, respectively, and should return an int value. As an example, given an array of size 10 with contents: {10, 9, 6, 1, 2, 4, 16, 8, 7, 5} The output should be: The largest number in the array is 16 The function should return -1 if the input is invalid. Place the array_max's function prototype in array_max.hpp and its implementation in array_max.cpp. The main function already contains some code, but you need to complete the requirements that is described inside the file.

Answer 1

CODE WITH EXPLANATION IS BELOW:-

#include <iostream>

using namespace std;

int array_max(int arr[], int n)

{ //here let's observe how this code works.

// let's take an array of size 3 arr={2,1,3}

// when we will call the function with araay_max(arr,3)

// n==1 will be false for the first recursion

// 1.therefore it will return max(arr[3-1],array_max(arr,2)), arr[3-1] = arr[2] = 3

//and again array_max will go in another recusrsion and check

//2.and therefore it will return max(arr[2-1],array_max(arr,1)), arr[2-1] = arr[1] = 1

//and again array_max will go in another recusrsion and check

// but this arr has only one element which is 2 therefore it return 2 to step 2

// and will compare between 2 and 1 and return 2 to step 1

// and there 2 and 3 will be compareed and 3 will be returned

// so basically the comarision is 1,2 then 2,3

if (n == 1)

return arr[0];

return max(arr[n-1], array_max(arr, n-1));

}

int main()

{

int arr[] = {10, 9, 6, 1, 2, 4, 16, 8, 7, 5}; // this the test array of size ten

int n = 10;

cout << array_max(arr, n); // printing what is returned by the araay_max

return 0;

}