01204212/codes/queues and stacks - ประวัติรุ่นแก้ไข

Jittat เมื่อ 01:50, 10 กันยายน 2559

2016-09-10T01:50:59Z

Jittat เมื่อ 01:20, 10 กันยายน 2559

2016-09-10T01:20:09Z

Jittat เมื่อ 23:52, 9 กันยายน 2559

2016-09-09T23:52:36Z

Jittat: หน้าที่ถูกสร้างด้วย ': ''This is part of 01204212'' This part takes linked list class (with iterator) from 01204212/codes/linked_lists to implement...'

2016-09-09T23:50:17Z

หน้าที่ถูกสร้างด้วย ': ''This is part of 01204212'' This part takes linked list class (with iterator) from 01204212/codes/linked_lists to implement...'

หน้าใหม่

: ''This is part of [[01204212]]''

This part takes linked list class (with iterator) from [[01204212/codes/linked_lists]] to implement queues and stacks with the same interface as in the Java Collection.

== Queue.java ==
I also included method printItems which shouldn't be part of the queue class, but it is useful when you debug your code for job queue 2.

<syntaxhighlight lang="java">
import java.util.NoSuchElementException;

public class Queue<T> {

private LinkedList<T> list;

Queue() {
list = new LinkedList<T>();
}

public boolean isEmpty() {
return list.isEmpty();
}

public T peek() {
if(!isEmpty()) {
return list.iterator().getVal();
} else {
return null;
}
}

public T remove() {
T res = poll();
if(res == null) {
throw new NoSuchElementException();
}
return res;
}

public T poll() {
if(! list.iterator().isEnded()) {
T val = peek();
list.removeHead();
return val;
} else {
return null;
}
}

public boolean add(T val) {
list.add(val);
return true;
}

// -------------- additional method for debugging -------
public void printItems() {
LinkedList<T>.Iterator head = list.iterator();
while(head != null) {
System.out.print("" + head.getVal() + " ");
head.next();
}
System.out.println();
}
}
</syntaxhighlight>

@@ แถว 1: / แถว 1: @@
 : ''This is part of [[01204212]]''
-This part takes linked list class (with iterator) from [[01204212/codes/linked_lists]] to implement queues and stacks with the same interface as in the Java Collection.  Some method is intentionally left out as an exercise.
+This part takes linked list class (with iterator) from [[01204212/codes/linked_lists]] to implement queues and stacks with the same interface as in the Java Collection.  '''Some method is intentionally left out as an exercise.'''
 == Queue.java ==
-I also included method printItems which shouldn't be part of the queue class, but it is useful when you debug your code for job queue 2.  Method <tt>poll</tt> has been left out as an exercise.  Note that method <tt>poll</tt> removes the head of the queue and returns it, but if the queue is empty it returns null.
+I also included method printItems which shouldn't be part of the queue class, but it is useful when you debug your code for job queue 2.
 <syntaxhighlight lang="java">
@@ แถว 38: / แถว 40: @@
      public T poll() {
-         // put your code here
+        // **********************************
+     }
@@ แถว 59: / แถว 63: @@
 == Stack.java ==
-Method <tt>pop</tt> that returns and removes the top of the stack has been left out as an exercise.
+'''Notes:''' Method <tt>pop</tt> that returns and removes the top of the stack has been left out as an exercise.
 <syntaxhighlight lang="java">
@@ แถว 83: / แถว 87: @@
      public T pop() {
-         // ... put your code here ...
+         // **********************************
+     }

@@ แถว 1: / แถว 1: @@
 : ''This is part of [[01204212]]''
-This part takes linked list class (with iterator) from [[01204212/codes/linked_lists]] to implement queues and stacks with the same interface as in the Java Collection.
+This part takes linked list class (with iterator) from [[01204212/codes/linked_lists]] to implement queues and stacks with the same interface as in the Java Collection.  Some method is intentionally left out as an exercise.
 == Queue.java ==
-I also included method printItems which shouldn't be part of the queue class, but it is useful when you debug your code for job queue 2.
+I also included method printItems which shouldn't be part of the queue class, but it is useful when you debug your code for job queue 2.  Method <tt>poll</tt> has been left out as an exercise.  Note that method <tt>poll</tt> removes the head of the queue and returns it, but if the queue is empty it returns null.
 <syntaxhighlight lang="java">
@@ แถว 38: / แถว 38: @@
      public T poll() {
-        if(! list.iterator().isEnded()) {
+         // put your code here
+     }
@@ แถว 65: / แถว 59: @@
 == Stack.java ==
 <syntaxhighlight lang="java">
 public class Stack<T> {
@@ แถว 87: / แถว 83: @@
      public T pop() {
-         if(list.isEmpty()) {
+         // ... put your code here ...
+     }

@@ แถว 60: / แถว 60: @@
+         }
          System.out.println();
+     }
+}
 </syntaxhighlight>