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Practice Questions for Recursion | Set 3
• Difficulty Level : Easy
• Last Updated : 09 Apr, 2021

Explain the functionality of below recursive functions.

Question 1

## C++

 `void` `fun1(``int` `n)``{``   ``int` `i = 0;  ``   ``if` `(n > 1)``     ``fun1(n - 1);``   ``for` `(i = 0; i < n; i++)``     ``cout << ``" * "``;``}` `// This code is contributed by shubhamsingh10`

## C

 `void` `fun1(``int` `n)``{``   ``int` `i = 0; ``   ``if` `(n > 1)``     ``fun1(n-1);``   ``for` `(i = 0; i < n; i++)``     ``printf``(``" * "``);``}`

## Java

 `static` `void` `fun1(``int` `n)``{``   ``int` `i = ``0``;  ``   ``if` `(n > ``1``)``     ``fun1(n - ``1``);``   ``for` `(i = ``0``; i < n; i++)``     ``System.out.print(``" * "``);``}`` ` `// This code is contributed by shubhamsingh10`

## Python3

 `def`  `fun1(n):``    ``i ``=` `0``    ``if` `(n > ``1``):``        ``fun1(n ``-` `1``)``    ``for` `i ``in` `range``(n):``        ``print``(``" * "``,end``=``"")` `# This code is contributed by shubhamsingh10`

## C#

 `static` `void` `fun1(``int` `n)``{``    ``int` `i = 0;``    ``if` `(n > 1)``        ``fun1(n-1);``    ``for` `(i = 0; i < n; i++)``        ``Console.Write(``" * "``);``}` `// This code is contributed by shubhamsingh10`

## Javascript

 ``

Answer: Total numbers of stars printed is equal to 1 + 2 + …. (n-2) + (n-1) + n, which is n(n+1)/2.

Question 2

## C++

 `#define LIMIT 1000``void` `fun2(``int` `n)``{``  ``if` `(n <= 0)``     ``return``;``  ``if` `(n > LIMIT)``    ``return``;``  ``cout << n <<``" "``;``  ``fun2(2*n);``  ``cout << n <<``" "``;``}` `// This code is contributed by shubhamsingh10`

## C

 `#define LIMIT 1000``void` `fun2(``int` `n)``{``  ``if` `(n <= 0)``     ``return``;``  ``if` `(n > LIMIT)``    ``return``;``  ``printf``(``"%d "``, n);``  ``fun2(2*n);``  ``printf``(``"%d "``, n);``}  `

## Java

 `int` `LIMIT = ``1000``;``void` `fun2(``int` `n)``{``    ``if` `(n <= ``0``) ``return``;``    ``if` `(n > LIMIT) ``return``;` `    ``System.out.print(String.format(``"%d "``, n));``    ``fun2(``2` `* n);``    ``System.out.print(String.format(``"%d "``, n));``}`

## Python3

 `LIMIT ``=` `1000``def` `fun2(n):``    ``if` `(n <``=` `0``):``        ``return``    ``if` `(n > LIMIT):``        ``return``    ``print``(n, end``=``" "``)``    ``fun2(``2` `*` `n)``    ``print``(n, end``=``" "``)` `# This code is contributed by shubhamsingh10`

## C#

 `int` `LIMIT = 1000``void` `fun2(``int` `n)``{``    ``if` `(n <= 0)``        ``return``;``    ``if` `(n > LIMIT)``        ``return``;``    ``Console.Write(n+``" "``);``    ``fun2(2*n);``    ``Console.Write(n+``" "``);``}` `// This code is contributed by Shubhamsingh10`

## Javascript

 ``

Answer: For a positive n, fun2(n) prints the values of n, 2n, 4n, 8n … while the value is smaller than LIMIT. After printing values in increasing order, it prints same numbers again in reverse order. For example fun2(100) prints 100, 200, 400, 800, 800, 400, 200, 100.
If n is negative, the function is returned immediately.
Please write comments if you find any of the answers/codes incorrect, or you want to share more information about the topics discussed above.

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