Expressions
Statements that evaluate to a value are called
expressions
.
You may be surprised how many statements do evaluate to a value. For
example, an assignment such as:
myVariable = 57;
is an expression; it evaluates to the value assigned, in this case,
57.
Note that the preceding statement assigns the value
57 to the variable myVariable.
The assignment operator
(=) does not test equality; rather it causes
whatever is on the right side (57) to be assigned
to whatever is on the left side (myVariable). All
of the C# operators (including assignment and equality) are discussed
later in this chapter (see Section 3.6).
Because myVariable = 57 is an expression that
evaluates to 57, it can be used as part of another
assignment operator, such as:
mySecondVariable = myVariable = 57;
What happens in this statement is that the literal value
57 is assigned to the variable
myVariable. The value of that assignment
(57) is then assigned to the second variable,
mySecondVariable. Thus, the value
57 is assigned to both variables. You can thus
initialize any number of variables to the same value with one
statement:
a = b = c = d = e = 20;