Related Articles
Find all factorial numbers less than or equal to n
• Difficulty Level : Easy
• Last Updated : 15 Mar, 2021

A number N is called a factorial number if it is the factorial of a positive integer. For example, the first few factorial numbers are
1, 2, 6, 24, 120, …
Given a number n, print all factorial numbers smaller than or equal to n.
Examples :

```Input : n = 100
Output : 1 2 6 24

Input : n = 1500
Output : 1 2 6 24 120 720```

A simple solution is to generate all factorials one by one until the generated factorial is greater than n.
An efficient solution is to find next factorial using previous factorial.

## C++

 `// CPP program to find all factorial numbers``// smaller than or equal to n.``#include ``using` `namespace` `std;` `void` `printFactorialNums(``int` `n)``{``    ``int` `fact = 1;``    ``int` `x = 2;``    ``while` `(fact <= n) {``        ``cout << fact << ``" "``;` `        ``// Compute next factorial``        ``// using previous``        ``fact = fact * x;` `        ``x++;``    ``}``}` `// Driver code``int` `main()``{``    ``int` `n = 100;``    ``printFactorialNums(n);``    ``return` `0;``}`

## Java

 `// Java program to find all factorial numbers``// smaller than or equal to n.` `class` `GFG``{``    ``static` `void` `printFactorialNums(``int` `n)``    ``{``        ``int` `fact = ``1``;``        ``int` `x = ``2``;``        ``while` `(fact <= n)``        ``{``            ``System.out.print(fact + ``" "``);``    ` `            ``// Compute next factorial``            ``// using previous``            ``fact = fact * x;``    ` `            ``x++;``        ``}``    ``}``    ` `    ``// Driver code``    ``public` `static` `void` `main (String[] args)``    ``{``        ``int` `n = ``100``;``        ``printFactorialNums(n);``    ``}``}` `// This code is contributed by Anant Agarwal.`

## Python3

 `# Python3 program to find all factorial``# numbers smaller than or equal to n.` `def` `printFactorialNums( n):``    ``fact ``=` `1``    ``x ``=` `2``    ``while` `fact <``=` `n:``        ``print``(fact, end ``=` `" "``)``        ` `        ``# Compute next factorial``        ``# using previous``        ``fact ``=` `fact ``*` `x``        ` `        ``x ``+``=` `1` `# Driver code``n ``=` `100``printFactorialNums(n)` `# This code is contributed by "Abhishek Sharma 44"`

## C#

 `// C# program to find all factorial numbers``// smaller than or equal to n.``using` `System;` `class` `GFG``{``    ``static` `void` `printFactorialNums(``int` `n)``    ``{``        ``int` `fact = 1;``        ``int` `x = 2;``        ``while` `(fact <= n)``        ``{``            ``Console.Write(fact + ``" "``);``    ` `            ``// Compute next factorial``            ``// using previous``            ``fact = fact * x;``    ` `            ``x++;``        ``}``    ``}``    ` `    ``// Driver code``    ``public` `static` `void` `Main ()``    ``{``        ``int` `n = 100;``        ``printFactorialNums(n);``    ``}``}` `// This code is contributed by vt_m.`

## PHP

 ``

## Javascript

 ``

Output:

`1 2 6 24`

Time Complexity : O(n)
If there are multiple queries, then we can cache all previously computed factorial numbers to avoid re-computations.
This article is contributed by Shubham Sagar. If you like GeeksforGeeks and would like to contribute, you can also write an article using contribute.geeksforgeeks.org or mail your article to contribute@geeksforgeeks.org. See your article appearing on the GeeksforGeeks main page and help other Geeks.
Please write comments if you find anything incorrect, or you want to share more information about the topic discussed above.

Attention reader! Don’t stop learning now. Get hold of all the important DSA concepts with the DSA Self Paced Course at a student-friendly price and become industry ready.

My Personal Notes arrow_drop_up