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C Bit Operations - August 06, 2008 at 13:10 PM by Amit Satpute
What are bitwise shift operators?
Answer
<< - Bitwise Left-Shift
Bitwise Left-Shift is useful when to want to MULTIPLY an integer (not floating
point numbers) by a power of 2.
Expression: a << b
This expression returns the value of a multiplied by 2 to the power of b.
>> - Bitwise Right-Shift
Bitwise Right-Shift does the opposite, and takes away bits on the right.
Expression: a >> b
This expression returns the value of a divided by 2 to the power of b.
Explain the use of bit fieild.
Answer
Bit Fields allow the packing of data in a structure.
This is especially useful when memory or data storage is at a premium
The maximum length of the field should be less than or equal to the integer word
length of the computer.some compilers may allow memory overlap for the
fields.Some store the next field in the next word.
C lets us do this in a structure definition by putting :bit length after the
variable:
struct pack
{
unsigned int funny_int:9;
}p;
Also, Boolean datatype flags can be stored compactly as a series of bits using
the bits fields. Each Boolean flag is stored in a separate bit..
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