c＃中的>>运算符是什么

Question

I am sure this has to as sweet and plain as butter. But I am not able get it or even find it.

It is related to colours in .net. I have taken a sample code from internet and trying to understand it. It takes a uInt as argument and do something to return a , r , g and b byte values. The method goes as:

private Color UIntToColor(uint color)
{
    byte a = (byte)(color >> 24);
    byte r = (byte)(color >> 16);
    byte g = (byte)(color >> 8);
    byte b = (byte)(color >> 0);
    return Color.FromArgb(a, r, g, b);
}

so what is >> here. For example,

color = 4278190335 // (blue color)

After processing

a = 255
r = 0
g = 0
b = 255

So can anyone help me to understand this?

Answer 1

It's in the docs

Right here

So, if you convert your value of 4278190335 to hex (because it's easier to see what's going on) you get 0xFF0000FF

So this line:

byte a = (byte)(color >> 24);

Will shift 0xFF0000FF 24 bits to the right to give you 0x000000FF. If you cast that to a byte, you will truncate off the most significant bits and end up with 0xFF or 255.

So you should be able to figure out what the other 3 lines do.

Answer 2

It's right-shift operator.

Basically, what it does is that it shifts all bits of the first operand to the right. The second operand specifies how "far" are bits shifted. For example:

uint value = 240; // this can be represented as 11110000
uint shift2 = value >> 2; // shift2 now equals 00111100
uint shift4 = value >> 4; // shift4 now equals 00001111

Good article on the subject is here .

Answer 3

>>是右移操作员。