Question

我创建了一个toString递归函数，当我在函数中首先更改为last以使其向后打印时，它不会输出任何内容。看起来它只是一遍又一遍地调用函数。

public String recursiveBackwardsString() {
    if (this.isEmptyList()) {
        return ("");
    } else {
        DoubleLinkedList < T > otherList = new DoubleLinkedList < T > ();
        otherList.copy(this);
        otherList.deleteNode(otherList.last.info);
        return ("" + this.last.info + otherList.recursiveBackwardsString());
    }
}

和我的toString有效：

public String recursiveToString() {
    if (this.isEmptyList()) {
        return ("");
    } else {
        DoubleLinkedList < T > otherList = new DoubleLinkedList < T > ();
        otherList.copy(this);
        otherList.deleteNode(otherList.first.info);
        return ("" + this.first.info + otherList.recursiveToString());
    }
}

有人能告诉我backwardsToString的问题吗？

public void deleteNode(T deleteItem){
DoubleLinkedListNode<T> current= new DoubleLinkedListNode<T>();
current=first;

if(this.isEmptyList()){
System.out.println("List is empty"); 
return;
}
else if(first.info.equals(deleteItem)){
 if(count>1){
   first=first.next;
   first.back=null;
   count=count-1;
   return;
 }

 else{
 first=null;
 last=first;
 count=0;
 return;
 }}
else{

 current=first.next;
 while(current!= null){
   if(current.info==deleteItem){
     current.back.next=current.next;
     current.next.back=current.back;
     count=count-1;
     return;
   }

 }}

System.out.print("Item not in the list");
return;
}

Answer 1

你需要改变这个：

else{

    current=first.next;
    while(current!= null){
        if(current.info==deleteItem){
            current.back.next=current.next;
            current.next.back=current.back;
            count=count-1;
            return;
        }

    }}

为：

else{

    current=first.next;
    while(current!= null){
        if(current.info.equals(deleteItem)){
            current.back.next=current.next;
            current.next.back=current.back;
            count=count-1;
            return;
        }

    }}

请注意==至.equals()。

如何创建递归向后toString（）

1 个答案: