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# Program to find Circumference of a Circle

• Difficulty Level : Medium
• Last Updated : 16 Feb, 2023

Given radius of a circle, write a program to find its circumference.
Examples :

```Input : 2
Output : Circumference = 12.566

Input : 8
Output : Circumference = 50.264```

In a circle, points lie in the boundary of a circle are at same distance from its center. This distance is called radius. Circumference of a circle can simply be evaluated using following formula.

```Circumference = 2*pi*r
where r is the radius of circle
and value of pi = 3.1415.``` ## C++

 `// CPP program to find circumference of circle ` `#include ` `using` `namespace` `std; ` ` `  `#define PI 3.1415 ` ` `  `double` `circumference(``double` `r) ` `{ ` `    ``double` `cir = 2*PI*r; ` `    ``return` `cir; ` `} ` ` `  `// driver function ` `int` `main() ` `{ ` `  ``double` `r = 5; ` `  ``cout << ``"Circumference = "`  `       ``<< circumference(r); ` `  ``return` `0; ` `}  `

## Java

 `// Java program to find circumference of circle ` `import` `java.io.*; ` ` `  `class` `Geometry { ` `     `  `    ``// utility function ` `    ``static` `double` `circumference(``double` `r){ ` ` `  `        ``double` `PI = ``3.1415``; ` `        ``double` `cir = ``2``*PI*r; ` `        ``return` `cir; ` `    ``} ` `     `  `    ``// driver function ` `    ``public` `static` `void` `main (String[] args) { ` ` `  `        ``double` `r = ``5``; ` `        ``double` `result = Math.round(circumference(r) * ``1000``) / ``1000.0``; ` `        ``System.out.println(``"Circumference = "``+ result); ` `    ``} ` `} ` ` `  `// This article is contributed by Chinmoy Lenka `

## Python3

 `# Python3 code to find  ` `# circumference of circle ` ` `  `PI ``=` `3.1415` ` `  `# utility function ` `def` `circumference(r): ` `    ``return` `(``2` `*` `PI ``*` `r) ` ` `  ` `  `# driver function ` `print` `(``'%.3f'` `%` `circumference(``5``)) ` ` `  `# This code is contributed by Saloni Gupta `

## C#

 `// C# program to find circumference of circle ` `using` `System; ` ` `  `class` `GFG { ` `     `  `    ``// utility function ` `    ``static` `double` `circumference(``double` `r){ ` ` `  `        ``double` `PI = 3.1415; ` `        ``double` `cir = 2*PI*r; ` `        ``return` `cir; ` `    ``} ` `     `  `    ``// driver function ` `    ``public` `static` `void` `Main () { ` ` `  `        ``double` `r = 5; ` `        ``double` `result = ` `              ``Math.Round(circumference(r) ` `                        ``* 1000) / 1000.0; ` `                         `  `        ``Console.WriteLine(``"Circumference = "` `                                  ``+ result); ` `    ``} ` `} ` ` `  `// This article is contributed by anuj_67. `

## PHP

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## Javascript

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Output :

`Circumference = 31.415`

Time Complexity: O(1), since there is no loop or recursion.

Auxiliary Space: O(1), since no extra space has been taken.

This article is contributed by Saloni Gupta . If you like GeeksforGeeks and would like to contribute, you can also write an article using write.geeksforgeeks.org or mail your article to review-team@geeksforgeeks.org. See your article appearing on the GeeksforGeeks main page and help other Geeks.