Microsoft Word - CPFinal2011SpringSolution

通識計算機程式設計期末考參考解答, 6/24/2011 1. 參考如下的 UML 類別圖, 撰寫 C# 敘述達成下列要求 : ( 假設 using System; 敘述已經包含於程式中 ) (a) 撰寫類別程式 Circle 代表圓形, 其中宣告私有 int 變數 radius 及 double 變數 area, 分別代表半徑及面積 ; 另有預設建構式設定 radius 為 1, 同時設定對應之 area 值 ; 正規建構式輸入 radius, 同時決定對應之 area 值, 屬性 Radius Area 分別傳回 radius area 之值, 此處不需處理例外情況 (6%) class Circle private int radius; private double area; 1/24

public Circle() radius = 1; area = Math.PI*radius*radius; public Circle(int radius) this.radius = radius; area = Math.PI * radius * radius; public int Radius get return radius; public double Area get return area; (b) 撰寫結構 Color, 包含三個公有 byte 變數 r g b, 及正規建構式分別設定 r g b 之值 (3%) struct Color public byte r; public byte g; public byte b; public Color(byte r, byte g, byte b) this.r = r; this.g = g; this.b = b; (c) 撰寫類別 ColoredCircle 繼承類別 Circle, 並宣告私有 Color 變數 color, 同時在宣告敘述中呼叫 Color 建構式 Color(0, 0, 0) 設 2/24

定 color 之初值 (6%) class ColoredCircle : Circle private Color color = new Color(0, 0, 0); (d) 撰寫類別 ColoredCircle 之正規建構式, 記得呼叫父類別之建構式 (6%) public ColoredCircle(int radius, Color c) : base(radius) color = c; (e) 撰寫類別 ColoredCircle 之成員函式 GetColor, 傳回 color (3%) public Color GetColor() return color; (f) 寫一段測試主程式, 設定顏色 red 之 r g b 為 (255, 0, 0), ColoredCircle 物件之 radius 為 2,color 為 red, 再利用它與繼承來的屬性函式及結構之公開變數, 輸出其半徑面積與顏色的 r g b 值如下圖 (6%) Color red = new Color(255, 0, 0); ColoredCircle cc = new ColoredCircle(2, red); Console.WriteLine("Colored circle cc is with " + "radius 0, area 1", cc.radius, cc.area); Color color = cc.getcolor(); 3/24

Console.WriteLine("Colored circle cc is with "+ "color: (0, 1, 2)", color.r, color.g, color.b); 2. 找出以下程式片段之錯誤, 並予更正. (a) (3%) 一個錯誤 class A private int i; public A(int i) this.i = i; public static int Func() return i; 靜態成員函式 Func 不應使用非靜態成員變數 i 改正 : 將成員函式 Func 改成非靜態 class A private int i; public A(int i) this.i = i; public int Func() return i; (b) (3%) 一個錯誤 class A 4/24

private int i; public A(int i) this.i = i; // 要把成員變數 i 乘以 2 public void Func(int i) i *= 2; 成員函式 Func 中乘以 2 的 i 是輸入的型式參數, 不是成員變數 i 所以成員變數 i 在 Func 中並未改變改正 : 去掉成員函式 Func 的輸入參數 class A private int i; public A(int i) this.i = i; public int I get return i; // 要把成員變數 i 乘以 2 public void Func() i *= 2; 5/24

(c) (3%). 一項錯誤 class A private int i; public A(int i) this.i = i; public int I get return i; class B : A private int j; public B(int i, int j) : base(i) this.j = j; public int J get return j; public void Func() j = i; 類別 B 的成員函式 Func 不能使用父類別 A 的私有成員變數 i 改正 : 將類別 A 中的成員變數 i 改宣告為 protected, 或改寫類別 B 的成員函式 Func 內容為 j = I; class A 6/24

protected int i; public A(int i) this.i = i; public int I get return i; class B : A private int j; public B(int i, int j) : base(i) this.j = j; public int J get return j; public void Func() j = i; 或 class A private int i; public A(int i) this.i = i; 7/24

public int I get return i; class B : A private int j; public B(int i, int j) : base(i) this.j = j; public int J get return j; public void Func() j = I; (d) (3%) 一個錯誤 class A private int i; public A(int i) this.i = i; public virtual int Func() return i; 8/24

class B : A private int j; public B(int i, int j) : base(i) this.j = j; // 要作為多型之用 public int Func() return j; 子類別欲作為多型之用的成員函式需加上 override 字樣改正 :Func 宣告時加上 override class A private int i; public A(int i) this.i = i; public virtual int Func() return i; class B : A private int j; public B(int i, int j) : base(i) 9/24

this.j = j; // 要作為多型之用 public override int Func() return j; (e) (3%) 一組錯誤 abstract class A public abstract int FunA(); abstract class B public abstract int FuncB(); class C : A, B int i; public C(int i) this.i = i; public int FuncA() return i; public int FuncB() return i; 10/24

只有 interface 才可多重繼承, 因此類別 B 不可同時繼承抽象類別 A B 改正 : 將抽象類別 A B 改宣告為 interface, 其中的函式去除 public abstract 修飾詞 interface A int FuncA(); interface B int FuncB(); class C : A, B private int i; public C(int i) this.i = i; public int FuncA() return i; public int FuncB() return i; 3. 試寫出下列程式的輸出 (12%) using System; namespace Final2011Problem3 11/24

class Program static void Main(string[] args) // 建立資料庫 Book[] book = new Book[7]; book[0] = new Book(" 紅樓夢 ", " 曹雪芹 ", " ", " 好讀 ", "2007", "857.49 5514 2007b v1"); book[1] = new Book(" 雪國千鶴古都 ", " 川端康成 ", " 高慧勤 ", " 桂冠 ", "1994", "861.57 2200-10"); book[2] = new Book(" 人鼠之間 ", " 史坦貝克 ", " 湯新楣 ", " 金楓 ", "1987", "874.57 5046-2"); book[3] = new Book(" 夢的解析 ", " 佛洛伊德 ", " 賴其萬 ", " 志文 ", "1985", "175.1 2532"); book[4] = new Book(" 國富論 ", " 亞當. 史密斯 ", " 謝宗林 ", " 先覺 ", "2000", "550.1842 5034 2000"); book[5] = new Book(" 天演論 ", " 赫胥黎 ", " 嚴復 ", " 台灣商務 ", "1967", "143.45 4412 1967"); book[6] = new Book(" 社會契約論 ", " 盧梭 ", " 何兆武 ", " 唐山 ", "1987", "571.9 2143-75"); DataBase db = new DataBase(book); // 資料搜尋 db.processquerybyauthor(" 川端康成 "); db.processquerybytitle(" 社會契約論 "); db.processquerybycallnumber("143.45 4412 1967"); class DataBase private Book[] book; public DataBase() book = null; 12/24

public DataBase(Book[] book) this.book = book; public void ProcessQueryByTitle(string title) for (int i = 0; i < book.length; ++i) if (book[i].title == title) book[i].displaydata(); Console.WriteLine(); public void ProcessQueryByAuthor(string author) for (int i = 0; i < book.length; ++i) if (book[i].author == author) book[i].displaydata(); Console.WriteLine(); public void ProcessQueryByCallNumber(string callnumber) for (int i = 0; i < book.length; ++i) if (book[i].callnumber == callnumber) book[i].displaydata(); 13/24

Console.WriteLine(); class Book private string title; private string author; private string translator; private string publisher; private string year; private string callnumber; public Book() title = null; author = null; translator = null; publisher = null; year = null; callnumber = null; public Book(string title, string author, string translator, string publisher, string year, string callnumber) this.title = title; this.author = author; this.translator = translator; this.publisher = publisher; this.year = year; this.callnumber = callnumber; public string Title get return title; public string Author 14/24

get return author; public string CallNumber get return callnumber; public void DisplayData() Console.WriteLine(title + "\t" + author + "\t" + translator + "\t" + publisher + "\t" + year + "\t" + callnumber); 4. 試寫出以下程式在下列狀況時的輸出 // 程式 Final2011Problem4 using System; using System.IO; namespace Final2011Problem4 class Program static void Main(string[] args) string filename = "Test.dat"; 15/24

int answer = Test(fileName); Console.WriteLine("answer = " + answer); static int Test(string filename) int result = 0; try StreamReader input = new StreamReader(fileName); Console.WriteLine(" 檔案開啟 "); try int ndataperline = int.parse(input.readline()); int i; string line; string[] datastring = new string[ndataperline]; int data; int sum = 0; while (!input.endofstream) line = input.readline(); datastring = line.split(' '); for (i = 0; i < ndataperline; ++i) data = int.parse(datastring[i]); sum += data; result = 105 / sum; catch (FormatException e) Console.WriteLine(" 格式錯誤 "); 16/24

catch (DivideByZeroException e) Console.WriteLine(" 除以 0 例外 "); catch (Exception e) Console.WriteLine( " 函式 Test 內層 try-catch 捕捉到例外 "); Console.WriteLine( " 函式 Test 內層 try-catch 再拋出例外 "); throw e; finally input.close(); Console.WriteLine(" 檔案關閉 "); catch(filenotfoundexception e) Console.WriteLine(" 檔案不存在 "); catch (Exception e) Console.WriteLine( " 函式 Test 外層 try-catch 捕捉到例外 "); return result; (a) (3%) 檔案 Test.dat 尚未建立 17/24

(b) (3%) 檔案 Test.dat 已在正確位置, 且內容為 3 1 2 3 4 5 6 (c) (3%) 檔案 Test.dat 已在正確位置, 且內容為 3 1 * 3 4 5 6 (d) (3%) 檔案 Test.dat 已在正確位置, 且內容為 3 1 2 3 4 5 18/24

5. 依據以下描述及程式框架, 完成指定程式你在答案卷只需寫下程式註解標示的部份 (6%) 程式描述 : 建立如下視窗介面, 由使用者輸入被加數及加數後, 按下確定按鈕, 即於對話盒顯示兩數之和假設被加數及加數之文字盒分別由視窗設計工具自動設定為 TextBox 物件 textbox1 及 textbox2, 而確定按鈕則設為 Button 物件 button1 // 檔案 MainForm.cs using System.Data; using System.Drawing; using System.Linq; using System.Text; using System.Windows.Forms; namespace Final2011Problem5 public partial class MainForm : Form public MainForm() InitializeComponent(); 19/24

private void button1_click(object sender, EventArgs e) //******************************************** // 在此加入必要之程式碼 //******************************************** int x = Convert.ToInt32(textBox1.Text); int y = Convert.ToInt32(textBox2.Text); int sum = x + y; MessageBox.Show(" 兩數和為 "+sum.tostring()); 6. 撰寫一個 C# 程式以模擬神奇寶貝 (Pocket Monster) 運動會中的 30 米賽跑為簡化問題, 只要寫主控台程式, 並在螢幕顯示各個神奇寶貝的位置, 最後顯示最先衝過終點最遠的贏家即可假設參賽的神奇寶貝有皮卡丘 (Pikachiu) 其每次移動的距離分別為 : 妙蛙種子 (Bulbasaur) 傑尼龜 (Squirtle), 皮卡丘 : rand.next() % 16 + 1 妙蛙種子 :(rand1.next() % 10) + (rand2.next() % 5) + 1 ( 需要兩個亂數產生器 ) 傑尼龜 : (rand.next() % 20-5) % 10 + 1 ( 沒錯, 可能往反方向跑 ) 其輸出可能如下圖 ( 殘念!! 皮卡丘先盛後衰, 輸了! 好討厭的感覺呀!): 20/24

以上述之測試場景撰寫程式, 不需撰寫額外內容不使用類別者, 最高得 13 分 ; 使用類別, 不使用多型者, 最高得 20 分 ; 正確使用使用類別及多型者, 最高得 25 分 (25%) using System; namespace Final2011Problem6 class Program static void Main(string[] args) const int TRACK_LENGTH = 30; const int N_MONSTERS = 3; PocketMonster[] monsters = new PocketMonster[N_MONSTERS]; monsters[0] = new Pikachiu(168); monsters[1] = new Bulbasaur(777, 545); monsters[2] = new Squirtle(66); bool finished = false; int i; while(!finished) for(i=0; i<n_monsters; ++i) monsters[i].run(); 21/24

Console.WriteLine(monsters[i].Name + " at " + monsters[i].position); if(monsters[i].position >= TRACK_LENGTH) finished = true; Console.WriteLine( "-------------------------------"); // check which monster runs farthest int maxlength = 0; for (i = 0; i < N_MONSTERS; ++i) if (monsters[i].position > maxlength) maxlength = monsters[i].position; // check for all winners (with possible tie // condition) for (i = 0; i < N_MONSTERS; ++i) if (monsters[i].position == maxlength) Console.WriteLine(monsters[i].Name + " wins "); abstract class PocketMonster private string name; protected int position = 0; 22/24

public PocketMonster(string name) this.name = name; public string Name get return name; public int Position get return position; abstract public void Run(); class Pikachiu : PocketMonster private Random rand; public Pikachiu(int seed) : base("pikachiu") rand = new Random(seed); public override void Run() position += rand.next() % 16 + 1; class Bulbasaur : PocketMonster private Random rand1; private Random rand2; public Bulbasaur(int seed1, int seed2) : base("bulbasaur") rand1 = new Random(seed1); rand2 = new Random(seed2); 23/24

public override void Run() position += (rand1.next() % 10) + (rand2.next() % 5) + 1; class Squirtle : PocketMonster private Random rand; public Squirtle(int seed) : base("squirtle") rand = new Random(seed); public override void Run() position += (rand.next() % 20-5) % 10 + 1; 7. ( 額外加分題, 至多 4%) 本課程中, 你覺得 : 甲那一部份最有趣? 為什麼? 乙那一部份最困難? 為什麼? 丙講義有何可改進之處? 丁怎麼做可以改進教學效果? 24/24