What does << do?

Question

Before tellimg me to google, please note that Google will not me search "<<" characters.

I have found the following:

data is a byte array.

int ResultChannel = data[1] + (data[2] << 8)

How does the << work?

Actually, [http://msdn.microsoft.com/en-us/library/a1sway8w.aspx](http://msdn.microsoft.com/en-us/library/a1sway8w.aspx) — Mohammad Dehghan, Mar 03 '13 at 14:03
Have you tried to google << characters? Tell me if you got any luck with it... — John V, Mar 03 '13 at 14:05
@TerryS But you get the point right? 10 minutes of research is not enough, as is stated in the FAQ. — antonijn, Mar 03 '13 at 14:06
Ok, tell me how to search for it if you cannot search these characters and do not know their meaning.. — John V, Mar 03 '13 at 14:06
"Before tellimg me to google, please note that Google will not me search "<<" characters." Come on! Be creative. Think of different search terms. — antonijn, Mar 03 '13 at 14:09

score 6 · Answer 1 · answered Mar 03 '13 at 14:02

6

Shift Left.

In C-inspired languages, the left and right shift operators are "<<" and ">>", respectively. The number of places to shift is given as the second argument to the shift operators. For example,
x = y << 2;
assigns x the result of shifting y to the left by two bits.

answered Mar 03 '13 at 14:02

Jakob Bowyer

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1

Not logical, it's bitwise. – Hauleth Mar 03 '13 at 14:02
2

@ŁukaszNiemier There are 2 types of shifts, arithmetic and logical. What would be a non bitwise shift? – axiom Mar 03 '13 at 14:05

score 2 · Answer 2 · answered Mar 03 '13 at 14:02

<< is a left shift operator

The left-shift operator (<<) shifts its first operand left by the number of bits specified by its second operand. The type of the second operand must be an int or a type that has a predefined implicit numeric conversion to int.

static void Main()
{
    int i = 1;
    long lg = 1;
    // Shift i one bit to the left. The result is 2.
    Console.WriteLine("0x{0:x}", i << 1);
    // In binary, 33 is 100001. Because the value of the five low-order 
    // bits is 1, the result of the shift is again 2. 
    Console.WriteLine("0x{0:x}", i << 33);
    // Because the type of lg is long, the shift is the value of the six 
    // low-order bits. In this example, the shift is 33, and the value of 
    // lg is shifted 33 bits to the left. 
    //     In binary:     10 0000 0000 0000 0000 0000 0000 0000 0000  
    //     In hexadecimal: 2    0    0    0    0    0    0    0    0
    Console.WriteLine("0x{0:x}", lg << 33);
}

score 2 · Answer 3 · answered Mar 03 '13 at 14:03

2

It a bit shift operator.

It shifts the bits to the left.

For example: the 5 << 3 returns a value that is 5 shifted three placed to the left. Five in binary is:

00000101

And if you shift that three places to the left you get:

00101000

Which is 40.

answered Mar 03 '13 at 14:03

antonijn

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What does << do?

3 Answers3