How to find largest in an integer array recursively (C++ Tutorial)

Finding largest in an integer array recursively

FindLargestRecursive() finds the largest in an integer array recursively and returns the largest value. It takes 4 parameters:

arr takes the array.

i takes the index of the array.

size takes the size of the array.

largest holds the largest element of the array.

Code of FindLargestRecursive()

int FindLargestRecursive( int arr[] , int i , int size , int largest )

{

      if ( i < size )

      {

            if ( arr[i] > largest )

                  largest = arr[i];

            return FindLargestRecursive( arr , i + 1 , size, largest );

      }

      return largest;

}

Summary of FindLargestRecursive()

FindLargestRecursive() starts from the first index of the array and recursively calls itself until i becomes equal to or greater than the size of array, at each function call the current element is checked against the largest element, if the current element at arr[i] is larger than the element in the largest variable, then the current element is saved in the largest variable.

At each recursive function call, the current index i is incremented by 1.

At the end, value in the largest variable is returned from the function.

Example (C++)

#include "stdafx.h"

#include "iostream"

#include "conio.h"

using namespace std;

int FindLargestRecursive( int arr[] , int i , int size , int largest )

{

      if ( i < size )

      {

            if ( arr[i] > largest )

                  largest = arr[i];

            return FindLargestRecursive( arr , i + 1 , size, largest );

      }

      return largest;

}

int main()

{

      const int size1 = 10;

      int arr1[size1] = {10,20,30,40,50,60,60,70,80,90};

      cout << FindLargestRecursive( arr1 , 1 , size1 , arr1[0] ); //    90

      cout << endl;

      const int size2 = 10;

      int arr2[size2] = {85,20,30,40,50,60,60,70,75,80};

      cout << FindLargestRecursive( arr2 , 1 , size2 , arr2[0] ); //    85

      cout << endl;

      const int size3 = 10;

      int arr3[size3] = {1,2,3,4,5,6,7,8,9,0};

      cout << FindLargestRecursive( arr3 , 1 , size3 , arr3[0] ); //      9

      cout << endl;

      const int size4 = 10;

      int arr4[size4] = {10,20,30,40,50,60,70,80,90,100};

      cout << FindLargestRecursive( arr4 , 1 , size4 , arr4[0] ); //    100

      cout << endl;

      const int size5 = 10;

      int arr5[size5] = {5,10,15,20,25,30,35,40,45,50};

      cout << FindLargestRecursive( arr5 , 1 , size5 , arr5[0] ); //    50

      cout << endl;

     

      _getche();

      return 0;

}

Output

90

85

9

100

50