# Number of n digit numbers that do not contain 9

Given a number n, find how many n digit number can be formed that does not contain 9 as it’s digit.

Examples:

Input : 1 Output : 8 Explanation : Except 9, all numbers are possible Input : 2 Output : 72 Explanation : Except numbers from 90 - 99 and all two digit numbers that does not end with 9 are possible.

Total numbers of n digit number that can be formed will be 9*10^(n-1) as except first position all digits can be filled with 10 numbers (0-9). If a digit 9 is eliminated from the list then total number of n digit number will be 8*9^(n-1).

Below is the implementation of above idea:

## C++

`// CPP program to find number of n` `// digit numbers that do not` `// contain 9 as it's digit` `#include <bits/stdc++.h>` `using` `namespace` `std;` `// function to find number of` `// n digit numbers possible` `int` `totalNumber(` `int` `n)` `{` ` ` `return` `8*` `pow` `(9, n - 1);` `}` `// driver function` `int` `main()` `{` ` ` `int` `n = 3;` ` ` `cout << totalNumber(n);` ` ` `return` `0;` `}` |

## Java

`// Java program to find number of ` `// n digit numbers that do not` `// contain 9 as it's digit` `import` `java.io.*;` `public` `class` `GFG` `{` ` ` `// function to find number of` `// n digit numbers possible` `static` `int` `totalNumber(` `int` `n)` `{` ` ` `return` `8` `* (` `int` `)Math.pow(` `9` `, n - ` `1` `);` `}` ` ` `// Driver Code` ` ` `static` `public` `void` `main (String[] args)` ` ` `{` ` ` `int` `n = ` `3` `;` ` ` `System.out.println(totalNumber(n));` ` ` ` ` `}` `}` `// This code is contributed by vt_m.` |

## Python3

`# python program to find number of n` `# digit numbers that do not` `# contain 9 as it's digit` `# function to find number of` `# n digit numbers possible` `def` `totalNumber(n):` ` ` ` ` `return` `8` `*` `pow` `(` `9` `, n ` `-` `1` `);` ` ` `# driver function` `n ` `=` `3` `print` `(totalNumber(n))` `# This code is contributed by Sam007` |

## C#

`// C# program to find number of ` `// n digit numbers that do not` `// contain 9 as it's digit` `using` `System;` `public` `class` `GFG` `{` ` ` `// function to find number of` `// n digit numbers possible` `static` `int` `totalNumber(` `int` `n)` `{` ` ` `return` `8 * (` `int` `)Math.Pow(9, n - 1);` `}` ` ` `// Driver Code` ` ` `static` `public` `void` `Main ()` ` ` `{` ` ` `int` `n = 3;` ` ` `Console.WriteLine(totalNumber(n));` ` ` ` ` `}` `}` `// This code is contributed by vt_m.` |

## php

`<?php` `// php program to find number of n` `// digit numbers that do not` `// contain 9 as it's digit` `// function to find number of` `// n digit numbers possible` `function` `totalNumber(` `$n` `)` `{` ` ` `return` `8 * pow(9, ` `$n` `- 1);` `}` ` ` `// driver function` `$n` `= 3;` `print` `(totalNumber(` `$n` `))` `// This code is contributed by Sam007` `?>` |

## Javascript

`<script>` `// Javascript program to find number of ` `// n digit numbers that do not` `// contain 9 as it's digit` `// function to find number of` `// n digit numbers possible` `function` `totalNumber(n)` `{` ` ` `return` `8 * Math.pow(9, n - 1);` `}` ` ` `// Driver code` ` ` `let n = 3;` ` ` `document.write(totalNumber(n));` ` ` ` ` `// This code is contributed by code_hunt.` `</script>` |

Output:

648

This article is contributed by **Dibyendu Roy Chaudhuri**. 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.

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