7.1.0 Assignments

Assignments

Assignments give a value to a variable, replacing any previous value the variable might have had:

_________________________________________________________________________________________________________ Assignments
-- assignment statement--variable reference----:= ---expression-----------
-function identifier -| -+= --|
|-= --|
|*= --|
-/= --
___________________________________________________________________

In addition to the standard Pascal assignment operator ( := ), which simply replaces the value of the varable with the value resulting from the expression on the right of the := operator, Free Pascal supports some c-style constructions. All available constructs are listed in table (7.1).

Table 7.1:

Allowed C constructs in Free Pascal

Assignment	Result
a += b	Adds b to a, and stores the result in a.
a -= b	Substracts b from a, and stores the result in a.
a *= b	Multiplies a with b, and stores the result in a.
a /= b	Divides a through b, and stores the result in a.

For these constructs to work, the -Sc command-line switch must be specified. Remark: These constructions are just for typing convenience, they don’t generate different code. Here are some examples of valid assignment statements:

 X := X+Y;
 X+=Y;      { Same as X := X+Y, needs -Sc command line switch}
 X/=2;      { Same as X := X/2, needs -Sc command line switch}
 Done := False;
 Weather := Good;
 MyPi := 4* Tan(1);

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