1042-130014 程式設計(下)

茂林是一個魔法師，但他長得像一個三角形。

茂林用他的法力，創造了一個環狀的空間。但因為他是一個三角形，所以這個環狀空間乍看之下，並不是環狀的。

這個環狀空間共有十個位置，讓你放置心儀對象的座號。並以先進先出的方式取用。

你是茂林的魔法棒，請為他創造出這個空間吧！

輸入說明

一個尺寸為 800Ｘ300 的視窗，使用 GridLayout 排版方式，擁有十個 Label 顯示心儀對象的座號（僅會輸入非零的 int）、一個輸入框作為輸入座號、一個 Button 作為取用。

輸出說明

• 座號若為 -1，表示尚未放值，請顯示 空。
• 輸入座號以及取用後，請即時更新座號列表。
• 當無座號可取用時，請彈出對話框警告。
• 當無空位可放置時，請彈出對話框警告。
• 當輸入非正的 int 時，請彈出對話框警告。

輸入、輸出範例

剛開始，Queue 都是空的

茂林輸入心儀女生得座號

系統將之加入到 Queue 中

在輸入六位後，先從 Queue 取用一位

當 Queue 是空的，茂林想取用的話，嗆他

當 Queue 是滿的，茂林還起貪念想加入新人，嗆他

茂林亂輸入非數字，嗆他

茂林亂輸入非正數字，嗆他

提示

Class JFrame from javax.swing.JFrame

• public void setSize(int width, int height)

  Resizes this component(Frame is a kind of Component) so that it has width width and height height.

• public void setLayout(LayoutManager mgr)

  Sets the layout manager(ex: GridLayout) for this container.

• public GridLayout(int rows, int cols)

  Creates a grid layout with the specified number of rows and columns. All components in the layout are given equal size.

• public Component add(Component comp)

  Appends the specified component to the end of this container.

• public void setVisible(boolean b)

  Shows or hides this component(Frame is a kind of Component) depending on the value of parameter b.

Class JOptionPane from javax.swing.JOptionPane

• public static void showMessageDialog(Component parentComponent, Object message) throws HeadlessException

  Brings up an information-message dialog titled "Message".

  parentComponent - determines the Frame in which the dialog is displayed; if null, or if the parentComponent has no Frame, a default Frame is used message - the Object to display

Class Integer from java.lang.Integer

• public static int parseInt(String s) throws NumberFormatException

  Parses the string argument as a signed decimal integer. The characters in the string must all be decimal digits, except that the first character may be an ASCII minus sign '-' ('\u002D') to indicate a negative value or an ASCII plus sign '+' ('\u002B') to indicate a positive value. The resulting integer value is returned, exactly as if the argument and the radix 10 were given as arguments to the parseInt(java.lang.String, int) method.

Class JTextField from javax.swing.JTextField

• public void setText(String text)

  Defines the single line of text this component will display. If the value of text is null or empty string, nothing is displayed.

• public void addActionListener(ActionListener l)

  Adds the specified action listener to receive action events from this button. Action events occur when a user presses or releases the mouse over this button. If l is null, no exception is thrown and no action is performed.

Class JLabel from javax.swing.JLabel

• public JLabel(String text)

  Creates a JLabel instance with the specified text. The label is aligned against the leading edge of its display area, and centered vertically.

• public void setText(String text) Defines the single line of text this component will display. If the value of text is null or empty string, nothing is displayed.

Class JButton from javax.swing.JButton

• public JButton(String text)

  Creates a button with text.

• public void addActionListener(ActionListener l)

  Adds the specified action listener to receive action events from this button. Action events occur when a user presses or releases the mouse over this button. If l is null, no exception is thrown and no action is performed.

Class ActionEvent from java.awt.event.ActionEvent

• public String getActionCommand()

  Returns the command string associated with this action. This string allows a "modal" component to specify one of several commands, depending on its state. For example, a single button might toggle between "show details" and "hide details". The source object and the event would be the same in each case, but the command string would identify the intended action.

Interface ActionListener from java.awt.event

• void actionPerformed(ActionEvent e)

  Invoked when an action occurs.

Class String from java.lang.String

• public boolean equals(Object anObject)

  Compares this string to the specified object(String is a kind of Object). The result is true if and only if the argument is not null and is a String object that represents the same sequence of characters as this object.