Programming and Graphics

86 Introduction to C++ Programming and Graphics

Shift operators

The commands:

short a=50;

short b;

b=a<<3;

cout << a << ", " << b << endl;

print on the screen:

50, 400

We note that the binary representation of 400 is:

0000000110010000

and conclude that the statementa<<3causes the binary string ofato be
shifted to the left by three places.

More generally, the statementa<<mcauses the binary string ofato be
shifted to theleftbymplaces. The statementa>>mcauses the binary string
ofato be shifted to therightbymplaces. When the binary string is shifted
to the left or to the right bymplaces, the numberais multiplied or divided by
2 m. Accordingly,<>are the left and rightShiftbitwise operators.

“and” operator

The statements:

short a=50;

shortb=a<<3;

cout << "a=" << a << " b=" << b << endl;

shortc=a&b;

cout << "c=" << c << endl;

print on the screen:

a=50 b=400

c=16

To understand thec=a&boperation in the penultimate line of the code, we
consider the binary representation of the three numbers involved,