System.Set

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C++

class RTL_DELPHIRETURN Set : public SetBase<T, (unsigned char)minEl, (unsigned char)maxEl>

Properties

Type	Visibility	Source	Unit	Parent
class	public	sysset.h	System	System

Description

Set is a C++ template for emulating the set types found in Delphi.

A set type is declared with three parameters:

Parameter	Usage
T	The type of the elements (usually int, char, or an enum type).
minEl	The minimum value the set can hold (this value cannot be less than 0.)
maxEl	The maximum value the set can hold (this value cannot be greater than 255.)

Two set types are distinct if any of the three template parameters are different:

Set <char, 'A', 'C'> s1;
Set <char, 'X', 'Z'> s2;
...
if (s1 == s2)   // ERROR: == not implemented for second set type

To create multiple instances of a Set type, use a typedef expression.

typedef Set <char, 'A','Z'> UPPERCASESet;

The declaration of a Set variable does not initialize the variable. You can declare the set types and initialize them by using the << operator, as shown in this example:

UPPERCASESet s1;
s1 << 'A' << 'B' << 'C';   // Initialize
UPPERCASESet s2;
s2 << 'X' << 'Y' << 'Z';   // Initialize

Note: To utilize the C++ streaming operators (<< and >>) with Set types, you must include the iostream library before the sysset. This occurs automatically if you include vcl.h or System.hpp. The following stream operators are defined:

 template <class T, unsigned char minEl, unsigned char maxEl> ostream& 
   operator <<(ostream& os, const Set<T, minEl, maxEl> & arg);
 template <class T, unsigned char minEl, unsigned char maxEl> istream&
   operator >>(istream& is, Set<T, minEl, maxEl> & arg)