Use Java Language.

// A StringSet is a collection of non-null strings, with no duplicates

// (i.e., no two elements may be equal).

public class StringSet {

private

public StringSet() {

}

// Throws an IllegalArgumentException if e is null, otherwise

// removes e from the set

public void remove(String e) {

}

// Returns the number of strings in the set

public int size() {

}