C++ Exercises: Find k largest elements in a given array of integers.

Last update on August 16 2025 12:56:03 (UTC/GMT +8 hours)

4. k Largest Elements in Array

Write a C++ program to find the k largest elements in a given array of integers.

Visual Presentation:

Pictorial Presentation: Find k largest elements in a given array of integers

Sample Solution:

C++ Code :

#include<iostream> // Header file for input/output stream
using namespace std; // Using the standard namespace

// Function to find and print the k largest elements in the array
void kLargest(int nums[], int n, int k)
{
    sort(nums, nums+n, greater<int>()); // Sorting the array in descending order using sort function

    cout << "\nLargest " << k << " Elements: "; // Output message indicating the k largest elements

    for (int i = 0; i < k; i++) // Loop to print the k largest elements
        cout << nums[i] << " "; // Output each of the k largest elements
}

int main() // Main function where the program execution starts
{
    int nums[] = {4, 5, 9, 12, 9, 22, 45, 7}; // Declaration and initialization of an integer array
    int n = sizeof(nums)/sizeof(nums[0]); // Determining the number of elements in the array

    cout << "Original array: "; // Output message indicating the original array is being displayed
    for (int i=0; i < n; i++) 
        cout << nums[i] <<" "; // Output each element of the array

    int k = 4; // Number of largest elements to be displayed
    kLargest(nums, n, k); // Calling function to find and print the k largest elements in the array
}

Sample Output:

Original array: 4 5 9 12 9 22 45 7 
Largest 4 Elements: 45 22 12 9

Flowchart:

For more Practice: Solve these Related Problems:

Write a C++ program to find the k largest elements in an array by partially sorting using the std::partial_sort algorithm.
Write a C++ program that uses a max-heap to extract the k largest numbers from a given array.
Write a C++ program to iterate through an array and store the k largest elements in a temporary array using selection logic.
Write a C++ program that reads an array and a value k, then outputs the k largest distinct elements using a multiset.

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