Visitor (C ++ implementation)

// Visitor. cpp: defines the entry point of the console application.
//

# Include "stdafx. H"
# Include <iostream>
# Include <string>

Using namespace STD;

Class visitor;

Class Element
{
Public:
Virtual ~ Element (){}

Virtual void accept (visitor & rvisitor) = 0;

Protected:
Element (){}
};

Class concreateelementa
: Public element
{
Public:
Concreateelementa (string S): state_a (s)
{

}
Virtual ~ Concreateelementa (){}

Virtual void accept (visitor & rvisitor );

String getstate ()
{
Return state_a;
}

PRIVATE:
String state_a;
 
};

Class concreateelementb
: Public element
{
Public:
Concreateelementb (string S): state_ B (s)
{
}

Virtual void accept (visitor & rvisitor );
String getstate ()
{
Return state_ B;
}
PRIVATE:
String state_ B;
};

Class visitor
{
Public:
Virtual ~ Visitor (){}

Virtual void visitconcreateelementa (concreateelementa * pconcreateelementa) = 0;
Virtual void visitconcreateelementb (concreateelementb * pconcreateelementb) = 0;

Protected:
Visitor (){}
};

Class concreatevisitora
: Public visitor
{
Public:
Virtual ~ Concreatevisitora (){}

Virtual void visitconcreateelementa (concreateelementa * pconcreateelementa)
{
Cout <"++" <pconcreateelementa-> getstate () <"++" <Endl;
}
Virtual void visitconcreateelementb (concreateelementb * pconcreateelementb)
{
Cout <"-----" <pconcreateelementb-> getstate () <"-----" <Endl;
}
};

Class concreatevisitorb
: Public visitor
{
Public:
Virtual ~ Concreatevisitorb (){}

Virtual void visitconcreateelementa (concreateelementa * pconcreateelementa)
{
Cout <"@" <pconcreateelementa-> getstate () + "" <"" <Endl;
}
Virtual void visitconcreateelementb (concreateelementb * pconcreateelementb)
{
Cout <"#####" <pconcreateelementb-> getstate () <"#####" <Endl;
}
};

Void concreateelementa: accept (visitor & rvisitor)
{
Rvisitor. visitconcreateelementa (this );
}

Void concreateelementb: accept (visitor & rvisitor)
{
Rvisitor. visitconcreateelementb (this );
}

Int _ tmain (INT argc, _ tchar * argv [])
{
Visitor * pvisitora = new concreatevisitora ();
Visitor * pvisitorb = new concreatevisitorb ();
Element * pelement = new concreateelementa (string ("XXXXX "));

Pelement-> Accept (* pvisitora );
Pelement-> Accept (* pvisitorb );

Element * pelement2 = new concreateelementb (string ("yyyyy "));

Pelement2-> Accept (* pvisitora );
Pelement2-> Accept (* pvisitorb );

Delete pelement;
Delete pelement2;
Delete pvisitora;
Delete pvisitorb;

Return 0;
}