What is the >> maths operator in C++

[DonMatteo]

Hi there,

I have a code with the following line:
long s = (ib-ia) >> 2

and I dont know what it means. When I debug it seems that the >> operator is used as a divide operator. What is exactly this operator >> in terms of mathematics?

Thanks,

Matteo

[Ganon11]

The >> operator is not strictly a mathematical operator - it is the right shift operator. Basically, any value is stored as a series of bits in C/C++ (or any other programming language). So if you have the number 23, your computer might store it as:

0001 1001

which is binary for 23.

Now, if I were to shift all the bits in the binary number to the right, I'd get a new number. Let's shift them to the right twice: the bit pattern is then:

0000 0110

which is 6. This is precisely what the >> operator does. The << operator is similar, but shifts in the left direction.

It just so happens that when you perform a shift operation:

a >> b;
// or
c << d;

these are the same as calculating a / (2**b) and c * (2**d), where ** means 'to the power of'.