Question

我有一个LinkedList类，我不允许为我的CS类更改。我还有一个程序，其中包含我的主要方法和一个名为Book的类，它可以存储有关书籍的信息（ISBN，价格，库存）。我的主要方法是将书籍放入链表。我虽然无法访问列表中的数据。

static void handleBooks(String Books,LinkedList BookInv)throws FileNotFoundException{
  File inputFile = new File(Books);
  Scanner input = new Scanner(inputFile);
  while(input.hasNextLine()){
     Scanner line = new Scanner(input.nextLine());
     BookInv.add(new Book(line.next(), Double.parseDouble(line.next()), Integer.parseInt(line.next()))); 
  }
  //System.out.println(BookInv.front.next.data.ISBN);

}

注释掉的线是我试图开始工作的线。关于一本书的数据也来自一个文件。

编辑：

public class LinkedList<E>{ 
   node front;
   int size; 
   public class node {
      E data;
      node next;
      node(E dataNext){
     data = dataNext;
     next = null;  
  }
  node(E data, node next){
     this.data = data;
     this.next = next;
  }
  void setData(E dataValue) {
     data = dataValue;
  }
  node getNext() {
     return next;
  } 
  void setNext(node nextValue) {
     next = nextValue;
  }

}

public void append(E data){
   if (front == null){
      front = new node(data);
   } else {
      node curr = front;
      while (curr.next != null){
       curr = curr.next;
   }
      curr.next = new node(data);
   }
   size++;
 }

 public void prepend(E data){
   front = new node(data,front);
   size++;
 }

public LinkedList(){
  front = null;
}//Empty linkedlist

public int size(){
  return size;
}

boolean isEmpty(){
  return front == null;
}

public void add(E Value){
  if(front == null){
     front = new node(Value);
  }else{
     node current = front;
     while(current.next !=null){
        current = current.next;
     }
     current.next = new node(Value);
  }
  size++;
}

public void add(int index, E value){
  if (index == 0){
      prepend(value);
   } else {
      node curr = front;
      for (int i = 0; i < index-1; i++){
       curr = curr.next;
   }
   curr.next = new node(value,curr.next);
   size++;
}
}

public E get(int index){
  if(isEmpty()){
     throw new IndexOutOfBoundsException();
  }
  node curr = front;
  //if 0 < index < size
  for(int i = 0; i < index; i++){
     curr = curr.next;
  }
  return curr.data;
}

public E remove(){
  if(isEmpty()){
     throw new IndexOutOfBoundsException();
  }
  E temp = front.data;
  front = front.next;
  size--;
  return temp;
}

public E remove(int index){

E temp;       

 if (index < 0 || index >= size){
    return null;
 }
 //special cases
 if (index == 0){
  temp = front.data;
    front = front.next;
 } else {
 //normal case
    node curr = front;
    for (int i = 0; i < index-1; i++){
       curr = curr.next;
    }
   temp = curr.next.data;
    curr.next = curr.next.next;
 }
 size--;
 return temp;
}
}

收到错误消息“BookInventory.java:49：错误：找不到符号符号：变量ISBN位置：E类型的可变数据

记录书籍的程序

0 个答案: