作者a127a127 (TDYa127)
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标题[试题] 96下 陈俊良 物件导向程式设计 期中考
时间Fri Apr 25 03:38:22 2008
课程名称︰物件导向程式设计 (Object-Oriented Programming)
课程性质︰系定必修
课程教师︰陈俊良
开课学院：电机资讯学院
开课系所︰资讯工程学系
考试日期（年月日）︰民国97年(西元2008年) 4月24日
考试时限（分钟）：120
是否需发放奖励金：是
（如未明确表示，则不予发放）
试题 :
1. Please write down the output of the following program. (4%)
1: class Expression {
2: public static void main(String[] args) {
3: System.out.println(1 / 2 + 1 / 3); // (a)
4: System.out.println(1F/ 2 + 1 / 3); // (b)
5: }
6: }
(注: 这题是要写(a)和(b)那两行会印出的东西。)
2. The following is a matrix multiplication program. It produces 10 13 28 40.
Please fill in the missing code. (20%)
1: class MatrixMultiplication {
2: public static void main(String[] args) {
3: int[][] a = {{0, 1, 2}, {3, 4, 5}};
4: int[][] b = {{0, 1}, {2, 3}, {4, 5}};
5: int[][] c = Matrix.multiplication(a, b);
6: System.out.println(c[0][0] + " " + c[0][1] + " " +
7: c[1][0] + " " + c[1][1]);
8: }
9: }
10: class Matrix {
11: static int[][] multiplication(int[][] a, int[][] b) {
12:
_(a)_ c = new int[
_(b)_.length][
_(c)_.length];
13: for (int i = 0; i <
_(d)_.length; i++) {
14:
_(e)_ ai = a[i];
15:
_(f)_ ci = c[i];
16: for (int j = 0; j <
_(g)_.length; j++) {
17: int cij = 0;
18: for (int k = 0; k <
_(h)_.length; k++) {
19: cij += ai
_(i)_ * b[k][j];
20: }
21: ci
_(j)_ = cij;
22: }
23: }
24: return c;
25: }
26: }
(注: 这题就是填空题，答案很多种的任选一个写就好。)
3. Please write down the output of the following program. (20%)
1: class HidingAndOverriding {
2: public static void main(String[] args) {
3: SubClass b1 = new SubClass();
4: SuperClass p1 = b1;
5: System.out.println(p1.variableA); // (a)
6: System.out.println(b1.variableA); // (b)
7: System.out.println(SubClass.variableA); // (c)
8: System.out.println(SuperClass.methodB(1)); // (d)
9: System.out.println(SubClass.methodB(2)); // (e)
10: System.out.println(p1.methodC(3)); // (f)
11: System.out.println(b1.methodC(4)); // (g)
12: System.out.println(p1.methodD(5)); // (h)
13: System.out.println(b1.methodD(6)); // (i)
14: System.out.println(b1.methodD()); // (j)
15: }
16: }
17: class SuperClass {
18: String variableA = "super";
19: static String methodB(int parameter) {
20: return Subclass.variableA + 1;
21: }
22: String methodC(int parameter) {
23: return variableA + 2;
24: }
25: String methodD(int parameter) {
26: return variableA + 3;
27: }
28: }
29: class SubClass extends SuperClass {
30: static String variableA = "sub";
31: static String methodB(int parameter) {
32: return variableA + 4;
33: }
34: String methodC(int parameter) {
35: return variableA + 5;
36: }
37: String methodD() {
38: return ((SuperClass) this).variableA + 6;
39: }
40: }
(注: 跟第一题一样)
4. The following program has 4 files. It produces (A((())CD)B). Please add
access modifiers as tightly as you can. For the default level, please
write "package". (20%)
1: import composite.*;
2: import composite.pattern.*;
3:
___(a)__ class Client {
4:
___(b)__ static void main(String[] args) {
5: Component c1 = new Composite(), c2 = new Composite(),
6: c3 = new Composite(), c4 = new Composite();
7: c1.add(new Leaf('A'));
8: c1.add(c2);
9: c1.add(new Leaf('B'));
10: c2.add(c3);
11: c2.add(new Leaf('C'));
12: c2.add(new Leaf('D'));
13: c3.add(c4);
14: System.out.println(c1.toString());
15: }
16: }
--------------------------------------------------------------------------
17: package composite;
18:
___(c)__ class Component {
19:
___(d)__ Composite parent;
20:
___(e)__ char name;
21:
___(f)__ void add(Component c) {
22: }
23: }
--------------------------------------------------------------------------
24: package composite;
25: inport java.util.Vector;
26:
_as_(c)_ class Composite extends Component {
27:
___(g)__ Vector<Component> children = new Vector<Component>();
28:
_as_(f)_ void add(Component c) {
29: children.add(c);
30: c.parent = this;
31: }
32:
___(h)__ Component getChild(int index) {
33: return children.elementAt(index);
34: }
35:
___(i)__ String toString() {
36: StringBuilder sb = new StringBuilder();
37: sb.append('(');
38: for (int i = 0; i < children.size(); i++)
39: sb.append(getChild(i).toString());
40: return sb.append(')').toString();
41: }
42: }
--------------------------------------------------------------------------
43: package composite.pattern;
44: import composite.Component;
45:
_as_(c)_ class Leaf extends Component {
46:
___(j)__ Leaf(char name) {
47: this.name = name;
48: }
49:
_as_(i)_ String toString() {
50: return name + "";
51: }
52: }
(注: 填空题，能限制越严格越好(能用private的就不要用其他的)。)
5. Please write down the output of the following program. (16%)
1: class OverriddenMethodInvocation {
2: public static void main(String[] args) {
3: SubClass b1 = new SubClass();
4: b1.method(4);
5: System.out.println(); // (a)
6: SuperClass p1 = new SuperClass();
7: b1.method(3);
8: System.out.println(); // (b)
9: }
10: }
11: class SuperClass {
12: void method(int parameter) {
13: if (parameter <= 0) return;
14: System.out.print(" super" + parameter);
15: parameter--;
16: method(parameter);
17: }
18: }
19: class SubClass extends SuperClass {
20: void method(int parameter) {
21: if (parameter <= 0) return;
// 这行老师说删掉
22: System.out.print(" sub" + parameter);
23: parameter--;
24: super.method(parameter);
25: }
26: }
(注: (a)和(b)是要写换行前印的东西，就是一整行输出。)
6. Please point out all compile-errors (don't care runtime-errors) and
write down the reasons. (20%)
1: clazz Polymorphism {
2: public static void main(String[] args) {
3: Book b1;
4: TextBook t1;
5: ComicBook c1;
6: Peanuts p1;
7: c1 = new Peanuts();
8: p1 = c1;
9: b1 = c1;
10: t1 = c1;
11: t1 = b1;
12: t1 = (TextBook) b1;
13: c1 = (TextBook) b1;
14: c1 = (ComicBook) b1;
15: }
16: }
17: class Book { }
18: class ComicBook extends Book { }
19: class Peanuts extends ComicBook { }
20: class TextBook extends Book { }
21: class TheJavaProgrammingLanguage extends TextBook { }
22: class HeadFirstJava extends ComicBook, TextBook { }
(注: 答案卷上有个范例 Line 1: class拼错。)
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1F：推 olala7846:感谢 06/15 16:08