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Python Program for Print Number series without using any loop
• Last Updated : 03 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
```

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``)`` ` `# 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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