How to quickly swap two arrays of same size in C++?

Given two arrays a[] and b[] of same size, we need to swap their contents.

Example :

Input : a[] = {1, 2, 3, 4}
        b[] = {5, 6, 7, 8}
Output : a[] = {5, 6, 7, 8}
         b[] = {1, 2, 3, 4}

A simple solution is to iterate over elements of both arrays and swap them one by one.

A quick solution is to use std::swap(). It can directly swap arrays if they are of same size.

// Illustrating the use of swap function
// to swap two arrays
#include <iostream>
#include <utility>
using namespace std;

// Driver Program
int main ()
{
    int a[] = {1, 2, 3, 4};
    int b[] = {5, 6, 7, 8};
    int n = sizeof(a)/sizeof(a[0]);

    swap(a, b);

    cout << "a[] = ";
    for (int i=0; i<n; i++)
        cout << a[i] << ", ";

    cout << "\nb[] = ";
    for (int i=0; i<n; i++)
        cout << b[i] << ", ";

    return 0;
}

Output :

a[] = 5, 6, 7, 8, 
b[] = 1, 2, 3, 4,

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