# Java Program for Print Number series without using any loop

• Last Updated : 05 Dec, 2018

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
```

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

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.

 `// 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`
Output:
```20 14 8 2 -4 2 8 14 20
```

Please refer complete article on Print Number series without using any loop for more details!

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