Arrays in C++

In this tutorial, we will learn about arrays in C++. We will cover the basics of declaring and using arrays, including accessing and modifying elements.

What is an Array

An array is a collection of elements of the same type stored in contiguous memory locations. It allows you to store multiple items under a single name and access them using an index.

An array of integers

Syntax

The syntax to declare an array in C++ is:

type arrayName[arraySize];

Working with Arrays

We will learn how to declare, initialize, access, and modify arrays in C++.


Example 1: Declaring and Initializing an Array

  1. Declare an integer array named arr with 5 elements.
  2. Initialize the array with values {1, 2, 3, 4, 5}.
  3. Print all the elements of the array.

C++ Program

#include <iostream>
using namespace std;
int main() {
    int arr[5] = {1, 2, 3, 4, 5};
    for (int i = 0; i < 5; i++) {
        cout << arr[i] << " ";
    }
    return 0;
}

Output

1 2 3 4 5

Example 2: Accessing Array Elements

  1. Declare an integer array named arr with 5 elements.
  2. Initialize the array with values {10, 20, 30, 40, 50}.
  3. Access and print the third element of the array.

C++ Program

#include <iostream>
using namespace std;
int main() {
    int arr[5] = {10, 20, 30, 40, 50};
    cout << "The third element is: " << arr[2] << endl;
    return 0;
}

Output

The third element is: 30

Example 3: Modifying Array Elements

  1. Declare an integer array named arr with 5 elements.
  2. Initialize the array with values {5, 10, 15, 20, 25}.
  3. Modify the second element of the array to 50.
  4. Print all the elements of the array.

C++ Program

#include <iostream>
using namespace std;
int main() {
    int arr[5] = {5, 10, 15, 20, 25};
    arr[1] = 50;
    for (int i = 0; i < 5; i++) {
        cout << arr[i] << " ";
    }
    return 0;
}

Output

5 50 15 20 25