Difference between revisions of "Variable parameter"
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{{MenuTranslate| page=Variable parameter}} | {{MenuTranslate| page=Variable parameter}} | ||
| − | Variable parameter (or Reference Parameter) is input and output parameter | + | '''Variable parameter''' (or Reference Parameter) is an ''input and output parameter'' |
| − | meaning it can be used for passing a value to a [[Function|function]] or | + | meaning it can be used for passing a value to a [[Function|function]] or [[Procedure|procedure]], |
| − | as well as to get back a value from function or procedure. It indicated by the use | + | as well as to get back a value from a function or procedure. It is indicated by the use |
of the [[Keyword|keyword]] [[Var|var]] in front of the formal parameter. | of the [[Keyword|keyword]] [[Var|var]] in front of the formal parameter. | ||
| − | + | A variable parameter can be considered a nickname to the actual argument given by the calling routine. When a procedure or function changes the value of a variable parameter they are actually changing the variable in the code that called the function or procedure. | |
| − | the | ||
Revision as of 12:19, 17 July 2016
Variable parameter (or Reference Parameter) is an input and output parameter meaning it can be used for passing a value to a function or procedure, as well as to get back a value from a function or procedure. It is indicated by the use of the keyword var in front of the formal parameter.
A variable parameter can be considered a nickname to the actual argument given by the calling routine. When a procedure or function changes the value of a variable parameter they are actually changing the variable in the code that called the function or procedure.
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;