# Extract ‘k’ bits from a given position in a number.

How to extract ‘k’ bits from a given position ‘p’ in a number?

Examples:

Input : number = 171 k = 5 p = 2 Output : The extracted number is 21 171 is represented as 0101011 in binary, so, you should get only 10101 i.e. 21. Input : number = 72 k = 5 p = 1 Output : The extracted number is 8 72 is represented as 1001000 in binary, so, you should get only 01000 i.e 8.

1) Right shift number by p-1.

2) Do bit wise AND of k set bits with the modified number. We can get k set bits by doing (1 << k) – 1.

## C

`// C program to extract k bits from a given ` `// position. ` `#include <stdio.h> ` ` ` `// Function to extract k bits from p position ` `// and returns the extracted value as integer ` `int` `bitExtracted(` `int` `number, ` `int` `k, ` `int` `p) ` `{ ` ` ` `return` `(((1 << k) - 1) & (number >> (p - 1))); ` `} ` ` ` `// Driver code ` `int` `main() ` `{ ` ` ` `int` `number = 171, k = 5, p = 2; ` ` ` `printf` `(` `"The extracted number is %d"` `, ` ` ` `bitExtracted(number, k, p)); ` ` ` `return` `0; ` `} ` |

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## Java

`// Java program to extract k bits from a given ` `// position. ` ` ` `class` `GFG { ` ` ` ` ` `// Function to extract k bits from p position ` ` ` `// and returns the extracted value as integer ` ` ` `static` `int` `bitExtracted(` `int` `number, ` `int` `k, ` `int` `p) ` ` ` `{ ` ` ` `return` `(((` `1` `<< k) - ` `1` `) & (number >> (p - ` `1` `))); ` ` ` `} ` ` ` ` ` `// Driver code ` ` ` `public` `static` `void` `main (String[] args) { ` ` ` `int` `number = ` `171` `, k = ` `5` `, p = ` `2` `; ` ` ` `System.out.println(` `"The extracted number is "` `+ ` ` ` `bitExtracted(number, k, p)); ` ` ` `} ` `} ` |

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## Python

`# Python program to extract k bits from a given ` `# position. ` ` ` `# Function to extract k bits from p position ` `# and returns the extracted value as integer ` `def` `bitExtracted(number, k, p): ` ` ` `return` `( ((` `1` `<< k) ` `-` `1` `) & (number >> (p` `-` `1` `) ) ); ` ` ` `# number is from where 'k' bits are extracted ` `# from p position ` `number ` `=` `171` `k ` `=` `5` `p ` `=` `2` `print` `"The extracted number is "` `, bitExtracted(number, k, p) ` |

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## C#

`// C# program to extract k bits from a given ` `// position. ` `using` `System; ` ` ` `class` `GFG { ` ` ` ` ` `// Function to extract k bits from p position ` ` ` `// and returns the extracted value as integer ` ` ` `static` `int` `bitExtracted(` `int` `number, ` `int` `k, ` `int` `p) ` ` ` `{ ` ` ` `return` `(((1 << k) - 1) & (number >> (p - 1))); ` ` ` `} ` ` ` ` ` `// Driver code ` ` ` `public` `static` `void` `Main() ` ` ` `{ ` ` ` `int` `number = 171, k = 5, p = 2; ` ` ` ` ` `Console.WriteLine(` `"The extracted number is "` ` ` `+ bitExtracted(number, k, p)); ` ` ` `} ` `} ` ` ` `//This code is contributed by Anant Agarwal. ` |

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## PHP

`<?php ` `//PHP program to extract ` `// k bits from a given ` `// position. ` ` ` `// Function to extract k ` `// bits from p position ` `// and returns the extracted ` `// value as integer ` `function` `bitExtracted(` `$number` `, ` `$k` `, ` `$p` `) ` `{ ` ` ` `return` `(((1 << ` `$k` `) - 1) & ` ` ` `(` `$number` `>> (` `$p` `- 1))); ` `} ` ` ` ` ` `// Driver Code ` ` ` `$number` `= 171; ` `$k` `= 5; ` `$p` `= 2; ` ` ` `echo` `"The extracted number is "` `, ` ` ` `bitExtracted(` `$number` `, ` `$k` `, ` `$p` `); ` ` ` `// This code is contributed by Ajit ` `?> ` |

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Output :

The extracted number is 21

This article is contributed by **Ujjwal Aryal**. 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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