*

│ English (en) │ suomi (fi) │ français (fr) │ русский (ru) │

*

standard Pascal

The symbol *, pronounced “asterisk”, is used in Pascal to

• indicate multiplication of numbers, or
• form the intersection of sets.

program asteriskDemo(input, output, stderr);

type
	day = (monday, tuesday, wednesday,
		thursday, friday, saturday, sunday);

var
	i: longint;
	n: real;
	m: set of day;

begin
	// multiplication operator
	i := 6 * 7;      // i becomes 42
	n := 6.0 * 7.0;  // n becomes 42.0
	
	// intersection operator
	m := [saturday, sunday] * [sunday, monday];
	// m is now {sunday}
end.

exponentiation

Furthermore, in FPC the exponentiation operator consisting of two consecutive asterisks ** exists. However, it isn't defined for any type by the standard system unit. Instead you have the chance to overload it on your own.

program exponentiation(input, output, stderr);

// make operator overloading available
{$mode objfpc}

operator ** (const base: integer; const exponent: integer): integer;
begin
	result := trunc(exp(ln(base) * exponent));
end;

begin
	writeLn(2 ** 10); // will print 1024
end.

For readily available overloads, the math and matrix unit can be included.

other appearances

In Pascal's years of childhood computer systems did not necessarily knew the comment delimiting characters opening and closing curly brace { }. To make block comments available on such systems an alternative syntax, the bigramms (* and *) are allowed, too, but they can't be interchanged willynilly: (* has to match a *), and can not match a } even though it is closing a block comment, too.

Also, if C like operators were allowed by the compiler directive {$COperator on}, the short syntax for i := i * n reads i *= n. But by doing so, you leave the domain of Pascal. Your code technically, mathematically speaking becomes wrong.

In ASCII, the character code decimal 42 (or hexadecimal 2A) is defined to be *.

see also

• system.power