/*js集合set類的實現*/function Set() {  this.dataStore = [];  this.add = add;//新增元素  this.remove = remove;//刪除元素  this.size = size;//集合的元素個數  this.union = union;//求并集  this.contains = contains;//判斷一個集合中是否包含某個元素  this.intersect = intersect;//交集  this.subset = subset;//判斷一個集合是否是另一個的子集  this.difference = difference;//求補集  this.show = show;//將集合元素顯示出來}function add(data) {  if (this.dataStore.indexOf(data) < 0) {    this.dataStore.push(data);    return true;  }  else {    return false;  }}function remove(data) {  var pos = this.dataStore.indexOf(data);  if (pos > -1) {    this.dataStore.splice(pos,1);    return true;  }  else {    return false;  }}function size() {  return this.dataStore.length;}function show() {  return "[" + this.dataStore + "]";}function contains(data) {  if (this.dataStore.indexOf(data) > -1) {    return true;  }  else {    return false;  }}function union(set) {  var tempSet = new Set();  for (var i = 0; i < this.dataStore.length; ++i) {    tempSet.add(this.dataStore[i]);  }  for (var i = 0; i < set.dataStore.length; ++i) {    if (!tempSet.contains(set.dataStore[i])) {      tempSet.dataStore.push(set.dataStore[i]);    }  }  return tempSet;}function intersect(set) {  var tempSet = new Set();  for (var i = 0; i < this.dataStore.length; ++i) {    if (set.contains(this.dataStore[i])) {      tempSet.add(this.dataStore[i]);    }  }  return tempSet;}function subset(set) {  if (this.size() > set.size()) {    return false;  }  else {    for(var member in this.dataStore) {      if (!set.contains(member)) {        return false;      }    }  }  return true;}function difference(set) {  var tempSet = new Set();  for (var i = 0; i < this.dataStore.length; ++i) {    if (!set.contains(this.dataStore[i])) {      tempSet.add(this.dataStore[i]);    }  }  return tempSet;}/*測試例子：求補集。屬于集合cis,不屬于集合it*/var cis = new Set();var it = new Set();cis.add("Clayton");cis.add("Jennifer");cis.add("Danny");it.add("Bryan");it.add("Clayton");it.add("Jennifer");var diff = new Set();diff = cis.difference(it);console.log(cis.show() + " difference " + it.show() + " -> " + diff.show());