Editing Logical conjunction (section)

==Applications in computer engineering{{anchor|software_AND}}==
[[File:AND Gate diagram.svg|thumb|right|AND [[logic gate]]]]
In high-level computer programming and [[digital electronics]], logical conjunction is commonly represented by an infix operator, usually as a keyword such as "<code>AND</code>", an algebraic multiplication, or the ampersand symbol <code>&</code> (sometimes doubled as in <code>&&</code>). Many languages also provide [[short-circuit evaluation|short-circuit]] control structures corresponding to logical conjunction.

Logical conjunction is often used for bitwise operations, where <code>0</code> corresponds to false and <code>1</code> to true:

* <code>0 AND 0</code> &nbsp;=&nbsp; <code>0</code>,
* <code>0 AND 1</code> &nbsp;=&nbsp; <code>0</code>,
* <code>1 AND 0</code> &nbsp;=&nbsp; <code>0</code>,
* <code>1 AND 1</code> &nbsp;=&nbsp; <code>1</code>.

The operation can also be applied to two binary [[words]] viewed as [[bitstring]]s of equal length, by taking the bitwise AND of each pair of bits at corresponding positions. For example:

* <code>11000110 AND 10100011</code> &nbsp;=&nbsp; <code>10000010</code>.

This can be used to select part of a bitstring using a [[Mask (computing)|bit mask]].  For example, <code>1001'''1'''101 AND 0000'''1'''000</code> &nbsp;=&nbsp; <code>0000'''1'''000</code> extracts the fourth bit of an 8-bit bitstring.

In [[computer networking]], bit masks are used to derive the network address of a [[subnetwork|subnet]] within an existing network from a given [[IP address]], by ANDing the IP address and the [[subnetwork#Binary subnet masks|subnet mask]].

Logical conjunction "<code>AND</code>" is also used in [[SQL]] operations to form [[database]] queries.

The [[Curry–Howard correspondence]] relates logical conjunction to [[product type]]s.