# Python Program for 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.

 `# 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``) `` ``# `

Output :

`20 14 8 2 -4 2 8 14 20`