Expression (programming)
An expression is in many programming a construct that according to a given semantics in relation to a context analyzed can be, so a value.
In many formal languages, expressions are one of the most important constructs, if not the only one. Some examples:
 Arithmetic expressions

2*3; 2(x − a); x^{2} = 2x; y= sin(x);
etc.  Propositional expressions

a und b; wenn b dann a; a oder nicht b;
etc.  Predicate logic expressions

wenn verheiratet(A, B) dann verheiratet(B, A); wenn Mensch(A) dann (Mann(A) oder Frau(A));
etc.
Expressions in programming languages

Literals (constants)
2
,3.14
... (But strings (strings) and symbols:"Hallo Welt"
,'c'
, ...) 
Variables :
x
,betragInEuro
,wochentagsNummer
, ... 
Features :
sin(phi)
,random()
,aktMonatsNummer()
, ... 
Operations :
2*3
,2(x  a)
,x^3
,cos(2*x + 3.14)
, ...  Combined terms, some of them with assignments or expression statements :
x++
,y
,y = x = 2*z
,y = sin(x)
, ...
In addition to expressions, declarations that define the context for the expressions are important in many formal languages . These are sometimes (especially in functional programming languages and scripting languages ) themselves viewed as expressions.
See also
literature
 Gert Smolka: Programming  an introduction to computer science with standard M . Second edition, Oldenbourg Verlag, Munich 2011, ISBN 9783486705171 .
 Anatoli Iwanowitsch Kitow: Programming and processing of large amounts of information . BG Verlagsgesellschaft, Leipzig 1972.
Web links
 Learn to code from the start (accessed February 29, 2016)
 Programming with Expressions (accessed February 29, 2016)
 Basics of Programming Literal Constants (accessed February 29, 2016)