The following is the specification of a Java set handling class useful in developing translators. A closely equivalent C# version appears lower on this page.
These classes - named IntSet - are functionally equivalent to the ones described in the text book, where they were named SymSet. In Java 1.4 one could not have "varargs" parameters, which are useful here. The SymSet classes are still available, but it is recommended that students replace references in pracs to the SymSet class with references to the IntSet class, and then both of the Java or C# versions behave in the same way, permitting constructor calls like
IntSet mySet = new IntSet(3, 67, 34); // Java 1.5 et seq and C# 1.0 et seq
rather than the clumsier
SymSet mySet = new SymSet(new int[] {3, 67, 34} ); // Java 1.4
import library.*;
class IntSet
// Simple set class
// P.D. Terry (p.terry@ru.ac.za)
public IntSet()
// Empty set constructor
public IntSet(int ... members)
// Variable args constructor IntSet(a) IntSet(a,b) etc
public Object clone()
// Value copy
public IntSet copy() {
// Another value copy
public boolean equals(IntSet s)
// Value comparison
public void incl(int i)
// Includes i in set
public void excl(int i)
// Excludes i from set
public boolean contains(int i)
// Returns true if i is a member of set
public boolean isEmpty()
// Returns true if set is empty
public int members()
// Returns number of members in set
public IntSet union(IntSet s)
// Set union
public IntSet intersection(IntSet s)
// Set intersection
public IntSet difference(IntSet s)
// Set difference
public IntSet symDiff(IntSet s)
// Set symmetric difference
public void write()
// Simple display of set on StdOut
public String toString()
// Returns string representation of set
} // IntSet
The following is the specification of a C# set handling class useful in developing translators. An closely equivalent Java version appears earlier on this page.
using Library;
class IntSet
// Simple set class
// P.D. Terry (p.terry@ru.ac.za)
public IntSet()
// Empty set constructor
public IntSet(params int[] members)
// Variable args constructor IntSet(a) IntSet(a,b) etc
public IntSet Clone()
// Value copy
public bool Equals(IntSet s)
// Value comparison of this set with s
public void Incl(int i)
// Includes i in this set
public void Excl(int i)
// Excludes i from this set
public bool Contains(int i)
// Returns true if i is a member of this set
public bool Contains(IntSet s) {
// Returns true if s is a subset of this set
public bool IsEmpty()
// Returns true if this set is empty
public bool IsFull() {
// Returns true if this set is a universe set
public void Fill()
// Creates a full universe set for this set
public void Clear() {
// Clear this set
public int Members()
// Returns number of members in this set
public IntSet Union(IntSet s)
// Set union of this set with s
public IntSet Difference(IntSet s)
// Set difference of this set with s
public IntSet Intersection(IntSet s)
// Set intersection of this set with s
public IntSet SymDiff(IntSet s)
// Set symmetric difference of this set with s
public override string ToString()
// Returns string representation of this set as a set of ints
public string ToCharSetString() {
// Returns string representation of this set as a set of chars
} // IntSet
The following is the specification of a Java 1.4 set handling class useful in developing translators. A closely equivalent C# 1.0 version appears lower on this page.
import library.*;
class SymSet
// Simple set class
// P.D. Terry (p.terry@ru.ac.za)
public SymSet()
// Empty set constructor
public SymSet(int[] members)
// Reasonable approximation to variable args constructor
// Usage - SymSet(new int[] {1}) SymSet(new int[] {a, b, c}) etc
public Object clone()
// Value copy
public SymSet copy() {
// Another value copy
public boolean equals(Symset s)
// Value comparison
public void incl(int i)
// Includes i in set
public void excl(int i)
// Excludes i from set
public boolean contains(int i)
// Returns true if i is a member of set
public boolean isEmpty()
// Returns true if set is empty
public int members()
// Returns number of members in set
public SymSet union(SymSet s)
// Set union
public SymSet intersection(SymSet s)
// Set intersection
public SymSet difference(SymSet s)
// Set difference
public SymSet symDiff(SymSet s)
// Set symmetric difference
public void write()
// Simple display of set on StdOut
public String toString()
// Returns string representation of set
} // SymSet
The following is the specification of a C# set handling class useful in developing translators. An closely equivalent Java version appears earlier on this page.
using Library;
class SymSet
// Simple set class
// P.D. Terry (p.terry@ru.ac.za)
public SymSet()
// Empty set constructor
public SymSet(params int[] members)
// Variable args constructor SymSet(a) SymSet(a,b) etc
public SymSet Clone()
// Value copy
public bool Equals(Symset s)
// Value comparison
public void Incl(int i)
// Includes i in set
public void Excl(int i)
// Excludes i from set
public bool Contains(int i)
// Returns true if i is a member of set
public bool IsEmpty()
// Returns true if set is empty
public void Fill()
// Creates a full universe set
public int Members()
// Returns number of members in set
public SymSet Union(SymSet s)
// Set union
public SymSet Intersection(SymSet s)
// Set intersection
public SymSet Difference(SymSet s)
// Set difference
public SymSet SymDiff(SymSet s)
// Set symmetric difference
public void Write()
// Simple display of set on StdOut
public override string ToString()
// Returns string representation of set
} // SymSet
Updated: 2012/08/22