Print Number series without using any loop

Problem – Givens Two number N and K, our task is to subtract a number K from N until number(N) is greater than zero, once the N becomes negative or zero then we start adding K until that number become the original number(N).
Note : Not allow to use any loop.

Examples :

Input : N = 15 K = 5  
Output : 15 10 5 0 1 5 10 15

Input : N = 20 K = 6
Output : 20 14 8 2 -4 2 8 14 20

Explanation – We can do it using recursion idea is that we call the function again and again until N is greater than zero (in every function call we subtract N by K). Once the number becomes negative or zero we start adding K in every function call until the number becomes the original number. Here we use a single function for both addition and subtraction but to switch between addition or subtraction function we used a Boolean flag.

Recommended: Please try your approach on {IDE} first, before moving on to the solution.

C++

// C++ program to Print Number 
// series without using loop 
#include <iostream> 
  
using namespace std; 
  
// function print series 
// using recursion 
void PrintNumber(int N, int Original, int K, bool flag) 
{ 
  
    // print the number 
    cout << N << " "; 
  
    // change flag if number 
    // become negative 
    if (N <= 0) 
        flag = !flag; 
  
    // base condition for 
    // second_case (Adding K) 
    if (N == Original && !flag) 
  
        return; 
  
    // if flag is true 
    // we subtract value until 
    // number is greater then zero 
    if (flag == true) { 
  
        PrintNumber(N - K, Original, K, flag); 
  
        return; 
    } 
  
    // second case (Addition ) 
    if (!flag) { 
  
        PrintNumber(N + K, Original, K, flag); 
  
        return; 
    } 
} 
  
// driver program 
int main() 
{ 
  
    int N = 20, K = 6; 
  
    PrintNumber(N, N, K, true); 
  
    return 0; 
} 

Java

// Java program to Print Number 
// series without using loop 
  
import java.io.*; 
import java.util.*; 
  
class GFG 
{ 
    public static void PrintNumber(int N, int Original, int K, boolean flag) 
    { 
  
        // print the number 
        System.out.print(N + " "); 
  
        // change flag if number 
        // become negative 
        if (N <= 0) 
            flag = !flag; 
  
        // base condition for 
        // second_case (Adding K) 
        if (N == Original && !flag) 
  
            return; 
  
        // if flag is true 
        // we subtract value until 
        // number is greater then zero 
        if (flag == true) 
        { 
            PrintNumber(N - K, Original, K, flag); 
            return; 
        } 
  
        // second case (Addition ) 
        if (!flag) 
        { 
            PrintNumber(N + K, Original, K, flag); 
            return; 
        } 
    } 
  
    public static void main (String[] args) 
    { 
        int N = 20, K = 6; 
        PrintNumber(N, N, K, true); 
    } 
} 
// This code is contributed by Mohit Gupta_OMG 

Python3

# Python program to Print Number 
# series without using loop 
  
def PrintNumber(N, Original, K, flag): 
    #print the number 
    print(N, end = " ") 
      
    # change flag if number 
    # become negative 
      
    if (N <= 0): 
        if(flag==0): 
            flag = 1
        else: 
            flag = 0
          
    # base condition for 
    # second_case (Adding K) 
      
    if (N == Original and (not(flag))): 
        return
      
    # if flag is true 
    # we subtract value until 
    # number is greater then zero 
      
    if (flag == True): 
        PrintNumber(N - K, Original, K, flag) 
        return
      
    # second case (Addition ) 
    if (not(flag)): 
        PrintNumber(N + K, Original, K, flag); 
        return
      
N = 20
K = 6
PrintNumber(N, N, K, True) 
  
# This code is contributed by Mohit Gupta_OMG 

C#

// C# program to Print Number 
// series without using loop 
using System; 
  
public class GFG { 
          
    // function print series 
    // using recursion 
    static void PrintNumber(int N, 
             int Original, int K, bool flag) 
    { 
      
        // print the number 
        Console.Write(N + " "); 
      
        // change flag if number 
        // become negative 
        if (N <= 0) 
            flag = !flag; 
      
        // base condition for 
        // second_case (Adding K) 
        if (N == Original && !flag) 
            return; 
      
        // if flag is true 
        // we subtract value until 
        // number is greater then zero 
        if (flag == true) 
        { 
            PrintNumber(N - K, Original, K, 
                                      flag); 
            return; 
        } 
      
        // second case (Addition ) 
        if (!flag) 
        { 
            PrintNumber(N + K, Original, K, 
                                      flag); 
            return; 
        } 
    } 
      
    // driver program 
    static public void Main () 
    { 
        int N = 20, K = 6; 
  
        PrintNumber(N, N, K, true); 
    } 
} 
  
// This code is contributed by vt_m. 

PHP

<?php 
// PHP program to Print Number 
// series without using loop 
  
// function print series 
// using recursion 
function PrintNumber($N, $Original,  
                     $K, $flag) 
{ 
  
    // print the number 
    echo($N . " "); 
  
    // change flag if number 
    // become negative 
    if ($N <= 0) 
        $flag = !$flag; 
  
    // base condition for 
    // second_case (Adding K) 
    if ($N == $Original && !$flag) 
  
        return; 
  
    // if flag is true 
    // we subtract value until 
    // number is greater then zero 
    if ($flag == true) { 
  
        PrintNumber($N - $K, $Original,  
                         $K, $flag); 
  
        return; 
    } 
  
    // second case (Addition ) 
    if (!$flag) { 
  
        PrintNumber($N + $K, $Original,  
                         $K, $flag); 
  
        return; 
    } 
} 
  
// Driver Code 
$N = 20; $K = 6; 
  
PrintNumber($N, $N, $K, true); 
  
// This code is contributed by Ajit. 
?> 

Output :

20 14 8 2 -4 2 8 14 20

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My Personal Notes

Recommended: Please try your approach on {IDE} first, before moving on to the solution.

C++

Java

Python3

C#

PHP

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