Difference between revisions of "Variable parameter"
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Variable parameter (or Reference Parameter) is input and output parameter | Variable parameter (or Reference Parameter) is input and output parameter | ||
meaning it can be used for passing a value to a [[Function|function]] or a [[Procedure|procedure]] | meaning it can be used for passing a value to a [[Function|function]] or a [[Procedure|procedure]] | ||
Revision as of 21:41, 8 January 2010
Variable parameter (or Reference Parameter) is input and output parameter meaning it can be used for passing a value to a function or a procedure as well as to get back a value from function or procedure. It indicated by the use of the keyword var in front of the formal parameter.
Variable parameter given a new nickname. The method refers to the same variable and changes made will affect the actual variable.
XOR swap
<delphi>
procedure XorSwap( var i,j:integer ); begin i := i xor j ; j := i xor j ; i := i xor j ; end;
</delphi>
OrderSmallBig
<delphi>
procedure OrderSmallBig( var a,b:integer ); begin if a > b then XorSwap( a, b ); end;
</delphi>
