Variable parameter

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Revision as of 16:06, 24 March 2012 by Vincent (talk | contribs) (Text replace - "delphi>" to "syntaxhighlight>")


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

  procedure XorSwap(  var i,j:integer );
  begin
    i := i xor j ;
    j := i xor j ;
    i := i xor j ;
  end;

OrderSmallBig

  procedure OrderSmallBig( var a,b:integer );
  begin
    if a > b then XorSwap( a, b );
  end;

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