SwapAlternate.cpp

// You have been given an array/list(ARR) of size N. You need to swap every pair of alternate elements in the array/list.
// You don't need to print or return anything, just change in the input array itself.

// Input Format :
// The first line contains an Integer 't' which denotes the number of test cases or queries to be run. Then the test cases follow.
// First line of each test case or query contains an integer 'N' representing the size of the array/list.
// Second line contains 'N' single space separated integers representing the elements in the array/list.

// Output Format :
// For each test case, print the elements of the resulting array in a single row separated by a single space.
// Output for every test case will be printed in a separate line.

// My Code
void swapAlternate(int *arr, int size)
{
    int temp;
    for(int i=0; i<size-1; i+=2){
        temp = arr[i];
        arr[i] = arr[i+1];
        arr[i+1] = temp;
    }
}

// Main Code
#include <iostream>
using namespace std;

#include "solution.h"

int main()
{
	int t;
	cin >> t;
	while (t--)
	{
		int size;
		cin >> size;
		int *arr = new int[size];
		for (int i = 0; i < size; i++)
		{
			cin >> arr[i];
		}
		swapAlternate(arr, size);
		for (int i = 0; i < size; i++)
		{
			cout << arr[i] << " ";
		}
		cout << endl;
		delete [] arr;
	}
}