Program to print the series 2, 1, 4, 3, 6, 5, …. up to N terms

Given a number N, the task is to print the below pattern upto N terms:

2, 1, 4, 3, 6, 5, …. N terms

Examples:



Input: N = 4
Output: 2, 1, 4, 3

Explanation:
Nth Term = (N % 2 == 0) ? (N - 1) : (N + 1)
1st term = (1 % 2 == 0) ? (1 - 1) : (1 + 1)
         = (1 + 1)
         = 2
2nd term = (2 % 2 == 0) ? (2 - 1) : (2 + 1)
         = (2 - 1)
         = 1
3rd term = (3 % 2 == 0) ? (3 - 1) : (3 + 1)
         = (3 + 1)
         = 4
4th term = (4 % 2 == 0) ? (4 - 1) : (4 + 1)
         = (4 - 1)
         = 3
Therefore, Series = 2, 1, 4, 3

Input: N = 7
Output: 2, 1, 4, 3, 6, 5, 8

Formula:

Nth Term = (N % 2 == 0) ? (N - 1) : (N + 1)

Below is the solution to above problem:

C++

filter_none

edit
close

play_arrow

link
brightness_4
code

// C++ program to print the series 
// 2, 1, 4, 3, 6, 5, …. up to N terms
#include <iostream>
using namespace std;
  
// Function to print the series
void printPattern(int N)
{
  
    for (int i = 1; i <= N; i++) {
  
        // Find and print the ith term
        cout <<" "<<((i % 2 == 0) ? (i - 1) : (i + 1));
    }
}
  
// Driver code
int main()
{
  
    // Get the value of N
    int N = 10;
  
    // Print the Series
    printPattern(N);
  
    return 0;
}

chevron_right






                        filter_none









Java














                                    filter_none




                                    edit

                                    close




                                    play_arrow




                                    link

                                    brightness_4

                                    code
                                




















// Java Program to print the series  


// 2, 1, 4, 3, 6, 5, …. up to N terms  


  


import java.util.*; 


import java.lang.*; 


import java.io.*; 


  


class GFG 


{ 


// Function to print the series  


static void printPattern(int N)  


{  


    


    for (int i = 1; i <= N; i++) {  


    


        // Find and print the ith term  


        System.out.print(" "+((i % 2 == 0) ? (i - 1) : (i + 1)));  


    }  


}  


    


// Driver code  


public static void main(String args[])  


{  


    


    // Get the value of N  


    int N = 10;  


    


    // Print the Series  


    printPattern(N);  


    


} 


}  



















                        chevron_right







                        filter_none









Python3














                                    filter_none




                                    edit

                                    close




                                    play_arrow




                                    link

                                    brightness_4

                                    code
                                




















# Python program to print the series  


# 2, 1, 4, 3, 6, 5, …. up to N terms  


  


# Function to print the series  


def printPattern(N): 


    for i in range(1, N + 1): 


          


        # Find and print the ith term  


        print(i - 1 if i % 2 == 0 


                    else i + 1, end = " ") 


  


# Driver code 


N = 10


printPattern(N) 


  


# This code is contributed by Shrikant13 



















                        chevron_right







                        filter_none









C#














                                    filter_none




                                    edit

                                    close




                                    play_arrow




                                    link

                                    brightness_4

                                    code
                                




















// C# program to print the series  


// 2, 1, 4, 3, 6, 5, …. up to N terms 


using System; 


  


class GFG 


{ 


// Function to print the series 


public void printPattern(int N) 


{ 


  


    for (int i = 1; i <= N; i++) 


    { 


  


        // Find and print the ith term 


        int a = ((i % 2 == 0) ?  


                      (i - 1) : (i + 1)); 


        Console.Write(" {0}", a); 


    } 


} 


  


// Driver code 


public static void Main() 


{ 


    GFG g = new GFG(); 


      


    // Get the value of N 


    int N = 10; 


  


    // Print the Series 


    g.printPattern(N); 


} 


} 


  


// This code is contributed 


// by Soumik 



















                        chevron_right







                        filter_none









PHP














                                    filter_none




                                    edit

                                    close




                                    play_arrow




                                    link

                                    brightness_4

                                    code
                                




















<?php 


// PHP program to print the series  


// 2, 1, 4, 3, 6, 5, …. up to N terms 


  


// Function to print the series 


function printPattern($N) 


{ 


  


    for ($i = 1; $i <= $N; $i++)  


    { 


  


        // Find and print the ith term 


        echo " " . (($i % 2 == 0) ?  


                    ($i - 1) : ($i + 1)); 


    } 


} 


  


// Driver code 


  


// Get the value of N 


$N = 10; 


  


// Print the Series 


printPattern($N); 


  


// This code is contributed 


// by ChitraNayal 


?> 



















                        chevron_right







                        filter_none











Output:


2 1 4 3 6 5 8 7 10 9






          
          
          
          

            

    

        My Personal Notes
        arrow_drop_up
    

    

        
        

            
            
        

    


Recommended Posts:
UdayKumar2
Check out this Author's contributed articles.
If you like GeeksforGeeks and would like to contribute, you can also write an article using contribute.geeksforgeeks.org or mail your article to contribute@geeksforgeeks.org. See your article appearing on the GeeksforGeeks main page and help other Geeks.
Please Improve this article if you find anything incorrect by clicking on  the "Improve Article" button below.