Grabbing n bits from a byte

Question

I\'m having a little trouble grabbing n bits from a byte.

I have an unsigned integer. Let\'s say our number in hex is 0x2A, which is 42 in decimal. In binary it looks li

Answer 1

Integers are represented inside a machine as a sequence of bits; fortunately for us humans, programming languages provide a mechanism to show us these numbers in decimal (or hexadecimal), but that does not alter their internal representation.

You should revise the bitwise operators &, |, ^ and ~ as well as the shift operators << and >>, which will help you understand how to solve problems like this.

The last 3 bits of the integer are:

x & 0x7

The five bits starting from the eight-last bit are:

x >> 3    // all but the last three bits
  &  0x1F // the last five bits.