Array traversal in C++

Introduction

We use array traversal to look at or use each item in a list one by one. It helps us check or change all items easily.

When you want to print all items in a list.

When you need to find a specific item in a list.

When you want to add or change values in every item.

When you want to count how many items meet a condition.

When you want to copy items from one list to another.

Syntax

C++

class ArrayTraversal {
public:
    int* array;
    int size;

    ArrayTraversal(int* input_array, int input_size) {
        array = input_array;
        size = input_size;
    }

    void traverse() {
        for (int index = 0; index < size; index++) {
            // Access array[index] here
        }
    }
};

The class holds the array and its size.

The traverse() method uses a for loop to visit each item by its index.

Examples

Edge case: Empty array. The loop does not run because size is 0.

C++

int numbers[] = {};
int size = 0;
ArrayTraversal traversal(numbers, size);
traversal.traverse();

Edge case: Array with one element. The loop runs once.

C++

int numbers[] = {42};
int size = 1;
ArrayTraversal traversal(numbers, size);
traversal.traverse();

Normal case: Array with multiple elements. The loop runs for each element.

C++

int numbers[] = {10, 20, 30, 40};
int size = 4;
ArrayTraversal traversal(numbers, size);
traversal.traverse();

Sample Program

This program creates an array of 5 numbers. It then creates an ArrayTraversal object with this array and its size. The traverse() method prints each element with its index.

C++

#include <iostream>

class ArrayTraversal {
public:
    int* array;
    int size;

    ArrayTraversal(int* input_array, int input_size) {
        array = input_array;
        size = input_size;
    }

    void traverse() {
        std::cout << "Array elements:" << std::endl;
        for (int index = 0; index < size; index++) {
            std::cout << "Element at index " << index << ": " << array[index] << std::endl;
        }
    }
};

int main() {
    int numbers[] = {5, 10, 15, 20, 25};
    int size = sizeof(numbers) / sizeof(numbers[0]);

    ArrayTraversal traversal(numbers, size);

    std::cout << "Before traversal:" << std::endl;
    traversal.traverse();

    return 0;
}

Important Notes

Time complexity is O(n) because we visit each element once.

Space complexity is O(1) extra space since we only use a few variables.

Common mistake: Using wrong loop limits causing out-of-bounds errors.

Use array traversal when you need to process every item. For searching, you might stop early if found.

Summary

Array traversal means visiting each item in order.

Use a for loop with an index from 0 to size-1.

It helps to read, print, or change all items in the array.