C++ Program To Traverse an Array

C++ Program To Traverse an Array

Last Updated : 19 Jul, 2022

Given an integer array of size N, the task is to traverse and print the elements in the array.

Examples:

Input: arr[] = {2, -1, 5, 6, 0, -3}
Output: 2 -1 5 6 0 -3

Input: arr[] = {4, 0, -2, -9, -7, 1}
Output: 4 0 -2 -9 -7 1

There are three ways to traverse the elements of an array in C++:

Using for loop.
Using for_each loop.
using range-based for loop.

Let's start discussing each of these methods in detail.

1. Using for Loop

Below is the approach for traversing an array using the for loop.

Approach:

A. Start a loop from 0 to N-1, where N is the size of the array.

for(i = 0; i < N; i++)

B. Access every element of the array with the help of

arr[index]

C. Print the elements.

cout << arr[i] << endl;

Below is the implementation of the above approach:

// C++ program to traverse 
// the array
#include <bits/stdc++.h>
using namespace std;

// Function to traverse and 
// print the array
void printArray(int* arr, int n)
{
    int i;

    cout << "Array: ";
    for (i = 0; i < n; i++) 
    {
        cout << arr[i] << "  ";
    }
}

// Driver code
int main()
{
    int arr[] = {2, -1, 5, 6, 0, -3};
    int n = sizeof(arr) / sizeof(arr[0]);

    printArray(arr, n);
    return 0;
}

 
// C++ program to traverse 
// the array#include <bits/stdc++.h>using namespace std;​// Function to traverse and // print the arrayvoid printArray(int* arr, int n){    int i;​    cout << "Array: ";    for (i = 0; i < n; i++)     {        cout << arr[i] << "  ";    }}​// Driver codeint main(){    int arr[] = {2, -1, 5, 6, 0, -3};    int n = sizeof(arr) / sizeof(arr[0]);​    printArray(arr, n);    return 0;}

Output

Array: 2  -1  5  6  0  -3

Time Complexity: O(n)

Auxiliary Space: O(1)

2. Using a for-each loop

for_each is a powerful STL algorithm to operate on range elements and apply custom-defined functions. It takes range starting and the last iterator objects as the first two parameters and the function object as the third one.
Below is the C++ program to implement the above approach:

// C++ program to traverse the 
// array using for_each loop
#include <bits/stdc++.h>
#include <iostream> 
using namespace std;

// Driver code
int main()
{
    int arr[] = {2, -1, 5, 6, 0, -3};
  
    // Traverse array with for_each 
    // using array's data type
    cout << "Traverse using array's data type";
    for(int x : arr)
      cout << x << " ";
    cout << endl;
  
    // Traverse array with for_each 
    // using auto keyword
    cout << "Traverse using auto keyword";
    for(auto x : arr)
      cout << x << " ";
    return 0;
}

 
// C++ program to traverse the 
// array using for_each loop#include <bits/stdc++.h>#include <iostream> using namespace std;​// Driver codeint main(){    int arr[] = {2, -1, 5, 6, 0, -3};      // Traverse array with for_each     // using array's data type    cout << "Traverse using array's data type";    for(int x : arr)      cout << x << " ";    cout << endl;      // Traverse array with for_each     // using auto keyword    cout << "Traverse using auto keyword";    for(auto x : arr)      cout << x << " ";    return 0;}

Output

Traverse using array's data type2 -1 5 6 0 -3 
Traverse using auto keyword2 -1 5 6 0 -3

Time Complexity: O(n)
Auxiliary Space: O(1)

3. Using range-based Loop

The range-based loop is the readable version of the for loop. The following code shows how to implement the above code using a range-based loop.

// C++ program to traverse the 
// array using range-based loop
#include <bits/stdc++.h>
#include <iostream> 
using namespace std;

// Driver code
int main()
{
    int arr[] = {2, -1, 5, 6, 0, -3};
  
    for (const auto &var : arr)  
    {  
      cout << var << " " ;  
    } 
    return 0;
}

 
// C++ program to traverse the 
// array using range-based loop#include <bits/stdc++.h>#include <iostream> using namespace std;​// Driver codeint main(){    int arr[] = {2, -1, 5, 6, 0, -3};      for (const auto &var : arr)      {        cout << var << " " ;      }     return 0;}

Output

2 -1 5 6 0 -3

Time Complexity: O(n)
Auxiliary Space: O(1)

C++ Program To Traverse an Array

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