3.0 - Bitwise Operator's

Bitwise

• Bitwise operators perform operations on bits
• The operand type shall be integral
• Return type is integral value

1. Bitwise Shift:

Syntax:

Left Shift :   shift-expression << additive-expression

                           (left operand)           (right operand)

Right Shift : shift-expression >> additive-expression

                          (left operand)            (right operand)

• Bitwise - Left Shift:

'Value' << 'Bits Count'

- Value : Is shift-expression on which bit shifting effect to be applied

- Bits count : Is additive-expression, by how many bit(s) the given “Value” to be shifted

• Bitwise - Right Shift:

'Value' >> 'Bits Count'

- Value : Is shift-expression on which bit shifting effect to be applied

- Bits count : Is additive-expression, by how many bit(s) the given “Value” to be shifted

Bitwise – Right Shift – Signed Valued

  "Signed Value' >> 'Bits Count'

- Same operation as mentioned in previous slide.

- But the sign bits gets propagated.

Bitwise – Shift

• Each of the operands shall have integer type
• The integer promotions are performed on each of the operands
• If the value of the right operand is negative or is greater than or equal to the width of the promoted left operand, the behaviour is undefined
• Left shift (<<) operator : If left operand has a signed type and non-negative value, and (left_operand * (2^n)) is representable in the result type, then that is the resulting value; otherwise, the behaviour is undefined

Operators – Comma

• The left operand of a comma operator is evaluated as a void expression (result discarded)
• Then the right operand is evaluated; the result has its type and value
• Comma acts as separator (not an operator) in following cases :-

– Arguments to function

– Lists of initialises (variable declarations)

– But, can be used with parentheses as function arguments such as :

– foo ((x = 2, x + 3)); // final value of argument is 5

 

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