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.

Recommended: Please try your approach on {IDE} first, before moving on to the solution.

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    // 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; }

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));     } }

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)

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.

PHP

 > (\$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 ?>

Output :

The extracted number is 21

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Improved By : jit_t

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