Method equals

collectiontopics/TypesForSets.java:13–16

(Object o)

  protected int i;
  SetType(int n) { i = n; }
  @Override public boolean equals(Object o) {
    return o instanceof SetType &&
      Objects.equals(i, ((SetType)o).i);
  }
  @Override public String toString() {
    return Integer.toString(i);
  }