Programming in C

Bit Operators
287
You should work out each of the operations from Program 12.2 with a paper and pencil
to verify that you understand how the results were obtained.The program was run on a
computer that uses 32 bits to represent an int.
In the fourth printf call, it is important to remember that the bitwise AND operator
has higher precedence than the bitwise OR, because this fact influences the resulting
value of the expression.
The fifth printf call illustrates DeMorgan’s rule, namely that ~(~a & ~b) is equal to
a | b and that ~(~a | ~b) is equal to a & b.The sequence of statements that follow
next in the program verifies that the exchange operation works as discussed in “The
Bitwise Exclusive-OR Operator” section.
The Left Shift Operator
When a left shift operation is performed on a value, the bits contained in the value are
literally shifted to the left. Associated with this operation is the number of places (bits)
that the value is to be shifted. Bits that are shifted out through the high-order bit of the
data item are lost, and 0s are always shifted in through the low-order bit of the value. So
if w1 is equal to 3,then the expression
w1 = w1