Question

我使用javascript创建一个列表，最后我有一个遍历列表并显示内容的迭代器。不幸的是我的迭代器进入无限循环而我无法调试它。

这是代码 - 如果你运行迭代器，你的浏览器会粉碎 - 其他所有功能似乎都运行良好。

function List(){
    this.listSize = 0;
    this.pos = 0;
    this.dataStore = []; 
    this.clearList = clear;
    this.find = find;
    this.toString = toString;
    this.insert = insert;
    this.append = append;
    this.remove = remove;
    this.front = front;
    this.end = end;
    this.prev = prev;
    this.next = next;
    this.length = length;
    this.currPos = currPos;
    this.moveTo = moveTo;
    this.getElement = getElement;
    this.length = length;
    this.contains = contains;
}

function append(element){
    this.dataStore[this.listSize++]=element;
}

function find(element){
    for(var i=0;i<this.dataStore.length; ++i){
        if(this.dataStore[i]==element){
            return i;
        }
    }
    return -1;
}

function remove(element){
    var foundAt = this.find(element);
        if(foundAt > -1){
            this.dataStore.splice(foundAt,1);
                --this.listSize;
                return true;
        }
        return false;
}

function length(){
    return this.listSize;
}

function toString(){
    return this.dataStore;
}

function insert(element, after){
    var insertPos = this.find(after);
    if(insertPos > -1){
        this.dataStore.splice(insertPos+1,0,element);
        ++this.listSize;
        return true;
    }
    return false;
}

function clear(){
    delete this.dataStore;
    this.dataStore = [];
    this.listSize = this.pos = 0;
}

function contains(element){
    for(var i = 0; i < this.dataStore.length; ++i){
        if(this.dataStore[i] == elemen){
            return true;
        }
    }
    return false
}


function front(){
    this.pos = 0;
}

function end(){
    this.pos = this.listSize-1;
}

function prev(){
    if(this.pos > 0){
        --this.pos;
    }
}

function next(){
    if(this.pos < this.listSize -1){
        ++this.pos;
    }
}

function currPos(){
    return this.pos;
}

function moveTo(position){
    this.pos = position;
}

function getElement(){
    return this.dataStore[this.pos];
}

var names = new List();
names.append("Clayton");
names.append("Raymond");
names.append("Cynthia");
names.append("Jennifer");
names.append("Bryan");
names.append("Danny");

names.front();
console.log(names.getElement());

names.next();
console.log(names.getElement());

names.next();
names.next();
names.prev();
console.log(names.getElement());


//iterator starts here 
for(names.front(); names.currPos() < names.length(); names.next()){
    console.log(names.getElement());
}

Answer 1

for pos >= listSize时for循环终止。但next()除非pos，否则pos < listSize - 1不会增加pos == listSize - 1。 next()后，pos不会增加pos。因此listSize - 1的最大值为{{1}}。因此循环永远不会终止。

List Iterator进入无限循环 - Javascript

1 个答案: