将节点插入链接列表
问题描述:
对于java来说,我相当新,所以如果这太可怕,请提前抱歉。基本上我想插入一个数字说,链接列表是[10 30 50 70]我想插入40,所以我输入下一个然后再下一个,现在我在50.我想插入之前,但是当我键入它只是返回之前,然后40 10 30 50 70]总= 4和电流为50将节点插入链接列表
public void insertAfter(long dd) {
Node newNode = new Node(dd); // insert a new node after current node;
newNode = current;
current = previous;
if (current != null) { // if current is not null, don't change it; otherwise set current to new node.
return;
}
else {
newNode = current;
}
}
public void insertBefore(long dd) {
Node newNode = new Node(dd); // insert a new node before current node, always set current to the new node
current = previous; // to be implemented
newNode = current;
}
这里是调用这两种方法并提供所述列表的代码。有什么建议么?
package hw4;
import java.io.*; // for I/O
class TestLinkList {
public static void main(String[] args) throws IOException
{
LinkList theList = new LinkList(); // new list
theList.insertFirst(70);
theList.insertFirst(50);
theList.insertFirst(30);
theList.insertFirst(10);
theList.reset();
while(true) {
System.out.print("Enter first letter of reset, ");
System.out.print("next, get, before, after, delete, exit: ");
System.out.flush();
int choice = getChar(); // get user's option
long value;
switch(choice)
{
case 'r': // reset (to first)
theList.reset();
theList.displayList();
break;
case 'e': // exit the while loop
break;
case 'n': // advance to next item
if(theList.getCurrent() != null) {
theList.nextLink();
theList.displayList();
} else
System.out.println("Can't go to next link");
break;
case 'g': // get current item
if(theList.getCurrent() != null) {
value = theList.getCurrent().dData;
System.out.println("Returned " + value);
}
else
System.out.println("List is empty");
break;
case 'b': // insert before current
System.out.print("Enter value to insert: ");
System.out.flush();
value = getInt();
theList.insertBefore(value);
theList.displayList();
break;
case 'a': // insert after current
System.out.print("Enter value to insert: ");
System.out.flush();
value = getInt();
theList.insertAfter(value);
theList.displayList();
break;
case 'd': // delete current item
if(theList.getCurrent() != null) {
value = theList.deleteCurrent();
System.out.println("Deleted " + value);
theList.displayList();
} else
System.out.println("Can't delete");
break;
default:
System.out.println("Invalid entry");
} // end switch
if (choice == 'e') break;
} // end while
} // end main()
public static String getString() throws IOException {
InputStreamReader isr = new InputStreamReader(System.in);
BufferedReader br = new BufferedReader(isr);
String s = br.readLine();
return s;
}
public static char getChar() throws IOException {
String s = getString();
return s.charAt(0);
}
public static int getInt() throws IOException {
String s = getString();
return Integer.parseInt(s);
}
}
答
由于这是作业,我会带领你走向正确的方向。
你insertAfter
方法是错误的。
您创建一个新节点的第一行。 你用当前覆盖这个newnode的第二行。
从这些错误开始。
最好的方法是用您的链接绘制图片。想想你需要怎么做才能将新节点放入列表中。如果你张贴`LinkList`和`显示列表()`太,什么不顺心还可以依据这些代码
将是一件好事。 – schnaader 2010-09-24 20:26:00