C language unknown & syntax

Question

I've found this in code, but I never encountered such thing as &, only &&

if ((code & 1) == 1){

Can you tell me what is it?

Punctuation can be hard to search for but look at bitwise operators. — doctorlove, Sep 28 '17 at 12:14
`&` is a [bitwise AND](https://en.wikipedia.org/wiki/Bitwise_operations_in_C) — Aziz, Sep 28 '17 at 12:15
Consider getting a C programming book... This is exactly the kind of thing you should look up in a book/documentation. — Lundin, Sep 28 '17 at 12:29

score 1 · Answer 1 · answered Sep 28 '17 at 12:18

This is bitwise operator. This means that some action is done with 'code' before comparasion happens. Wikipedia says:

A bitwise AND takes two equal-length binary representations and performs the logical AND operation on each pair of the corresponding bits, by multiplying them. Thus, if both bits in the compared position are 1, the bit in the resulting binary representation is 1 (1 × 1 = 1); otherwise, the result is 0 (1 × 0 = 0 and 0 × 0 = 0).

By the way, there is such thread but about C++ not C, here.

score 0 · Answer 2 · answered Sep 28 '17 at 12:16

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It's a bitwise and operator. It checks that the first bit of code is 1, so it checks the code is odd.

answered Sep 28 '17 at 12:16

Alexey Kozhevnikov

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score 0 · Answer 3 · answered Sep 28 '17 at 12:17

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& is binary AND operator copies a bit to the result if it exists in both operands.

For example:

(A & B) = 12, i.e., 0000 1100

answered Sep 28 '17 at 12:17

STF

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score 0 · Accepted Answer · answered Sep 28 '17 at 12:23

It's the bitwise and operator:

/* binary: 0100, 0010 and 0111*/
int x = 4, y = 2, z = 7;

/* then: */
printf("x & y = %d\n", x&y);
printf("x & z = %d\n", x&z);
printf("y & z = %d\n", y&z);

Output:

x & y = 0 x & z = 4 y & z = 2

You have the same for the or operation:

/* then: */
printf("x | y = %d\n", x&y);
printf("x | z = %d\n", x&z);
printf("y | z = %d\n", y&z);

Output:

x | y = 6
x | z = 7 
y | z = 7

So in your case, the if ((code & 1) == 1) is a test to know if less significant bit is raised in code

C language unknown & syntax

4 Answers4