java linkedlist实现队列_JAVA专题七：用LinkedList实现栈与队列
用LinkedList实现一个栈
"栈"有进也被称为"后进先出"的容器。同其他Java容器一样，压进去与弹出来的东西都是Object，所以除非你只用Object的功能，否则就必须对弹出来的东西进行类型转换。
LinkedList的方法能直接实现栈的功能，所以你完全可以不写stack而直接使用LinkedList。
Making a stack from a LinkedList
A stack is sometimes referred to as a “last-in, first-out”
(LIFO) container. That is, whatever you “push” on the stack last
is the first item you can “pop” out. Like all of the other
containers in Java, what you push and pop are Objects, so you must
cast what you pop, unless you’re just using Object behavior.
Comment
The LinkedList has methods that directly implement stack
functionality, so you can also just use a LinkedList rather than
making a stack class. However, a stack class can sometimes tell the
story better:
package com.tao.zhu;
import java.util.*;
class Weekdays {
static final
String[] weekdays = {"Mon", "Tue", "Wed", "Thu", "Fri",
"Sat",
"Sun"};
}
public class StackL {
private
LinkedList list = new LinkedList();
public void
push(Object v) {
list.addFirst(v);
}
public
Object top() {
return list.getFirst();
}
public
Object pop() {
return list.removeFirst();
}
public
static void main(String[] args) {
StackL stack = new StackL();
for (int i = 0; i < 7; i++) {
stack.push(Weekdays.weekdays[i]);
}
System.out.println(stack.top());
System.out.println(stack.top());
System.out.println(stack.pop());
System.out.println(stack.pop());
System.out.println(stack.pop());
}
} ///:~
Output:
Sun
Sun
Sun
Sat
用LinkedList实现一个队列
队列是一个“先进先出”容器。你放东西的顺序也取东西的顺序。LinkedList有支持队列功能的方法，所以它也能当作队列来使用。
Making a queue from a LinkedList
A queue is a “first-in, first-out” (FIFO) container. That
is, you put things in at one end, and pull them out at the other.
So the order in which you put them in will be the same order that
they come out. LinkedList has methods to support queue behavior, so
these can be used in a Queue class:
Fripackage com.tao.zhu;
import java.util.LinkedList;
public class QueueL {
private
static LinkedList list = new LinkedList();
public void
put(Object v) {
list.addFirst(v);
}
public
Object get(){
return
list.removeLast();
}
public
boolean isEmpty(){
return
list.isEmpty();
}
public
static void main(String[] args) { QueueL queuel = new QueueL();
//for(int i=0; i
// queuel.put(Weekdays.weekdays[i]);
for(int i=0; i<5; i++)
queuel.put(Integer.toString(i));
while(!queuel.isEmpty())
System.out.println(queuel.get());
}
}
Output:
0
1
2
3
4
---The end