Learning C# 2005: Get Started with C# 2.0 and .NET Programming (2nd Edition)

3.7. 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 assignedin 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 ). Chapter 4 discusses some of the more useful C# operators (including assignment and equality).

Because myVariable = 57 is an expression that evaluates to 57, it can be used as part of another assignment, 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 assign a value to any number of variables with one statement using the assignment operator ( = ), as in the following:

int a,b,c,d,e; a = b = c = d = e = 20;

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