Q1)
a) null
b) not equal
c) 5
d)(0,1) (1,2) (2,3)
e) E
f) (i) D (ii) E
g)
7
10
7
9
h)m,a,x,e,
Q2)
a)
b)
Q3)
a)
Error 2
Hello C
Hello D
b)
Error 4
Hello C
Hello D
c)
Hello A
Error 2
Hello C
Hello D
d)
Hello A
Error 4
Hello C
Hello D
e)
Hello A
Hello B
Result is 3
Hello C
Hello D
f)
Hello A
Hello B
Error 3
Hello C
Hello D
Q4) a)
Suppse Vector v is a vector consists of String. Write a short program to find
the number of strings in vector v that contain substring abc.
1:import java.util.*;
2:
3:public class CountString {
4: public static int countString(Vector v, String sub) {
5: int count = 0;
6: for(int i=0; i < v.size(); i++) {
7: if(((String)v.get(i)).indexOf(sub) >= 0) {
8: count++;
9: }
10: }
11: return count;
12: }
13:
14: public static void main(String[] args) {
15: // for testing
16: Vector v = new Vector();
17: v.add("abcdef");
18: v.add("cgefgh");
19: v.add("cdeabccd");
20: System.out.println(countString(v, "abc"));
21: }
22:}
Q5)
(a)
1:import java.io.*;
2:
3:public class ProgramA {
4: public static void writeString(OutputStream out, String s) {
5: if(out !=null) {
6: for(int i = 0; i < s.length(); i++) {
7: int x = s.charAt(i);
8: try {
9: out.write(x);
10: } catch (IOException ex) {
11: }
12: }
13: }
14: }
15:
16: public static void main(String[] args) {
17: writeString(System.out, "hello");
18: }
19:}
(b)
1:public class ProgramB {
2: public static void main(String[] args) {
3: double a = 0;
4: try {
5: a = Double.parseDouble(args[0]);
6: double c = a/0;
7: } catch (NumberFormatException ex) {
8: // do nothing
9: }
10:
11: if(a > 10000) {
12: System.out.println("args[0] is bigger than 10000.");
13: }
14: }
15:}
(c)
1:import java.util.*;
2:
3:public class ProgramC {
4: public static void main(String[] args) {
5: LinkedList list = new LinkedList();
6: for(int i = 0; i < args.length; i++) {
7: list.add(args[i]);
8: }
9:
10: int[] array = {1,2,3};
11: for(int i = 0; i < array.length; i++) {
12: list.add(new Integer(array[i]));
13: }
14: }
15:}
(d)
1:import java.util.*;
2:import java.awt.*;
3:
4:public class ProgramD {
5: private LinkedList list = new LinkedList();
6:
7: public ProgramD() {
8: list.add(Color.red);
9: list.add(Color.blue);
10: list.add(Color.green);
11: }
12:
13: public Color firstColor() {
14: return (Color)list.get(0);
15: }
16:}
(e)
1:public class ProgramE {
2: public static void main(String[] args) {
3: double x = 5.3, y =7.7;
4: int sum; // you are not allowed to change this line
5: sum = (int)(x + y);
6: }
7:}
(f)
no error.
Q6
int count = 0;
if(f.isDirectory()) {
return -1;
} else {
String[] files = file.list();
for(int i = 0; i < files.length; i++) {
if(files.[i].endsWith("." + ext") {
count++;
}
}
}
return count;
Q7)
1:import java.applet.*;
2:import java.awt.*;
3:import javax.swing.*;
4:
5:public class ColorLabel extends Applet {
6: public void init() {
7: setLayout(new BorderLayout());
8: JLabel label = new JLabel(getParameter("text"));
9: int r = Integer.parseInt(getParameter("red"));
10: int g = Integer.parseInt(getParameter("green"));
11: int b = Integer.parseInt(getParameter("blue"));
12: label.setOpaque(true);
13: label.setBackground(new Color(r,g,b));
14: add(label);
15: }
16:}
Q8
1:import java.awt.*;
2:import javax.swing.*;
3:import java.awt.event.*;
4:
5:public class WhoAmI extends JFrame implements ActionListener {
6: private JLabel topLabel = new JLabel();
7: private JPanel middlePanel = new JPanel(new GridLayout(2,5)) ;
8: private JLabel bottomLabel = new JLabel();
9: private JButton[] buttons;
10: private Container contentPane = getContentPane();
11: private String[] names = {"Apu", "Bart", "Burns", "Homer", "Krusty", "Lisa",
: "Maggie", "Marge", "Moe", "Ned"};
12: private String who;
13: private int trial = 0;
14: private int correct = 0;
15:
16: public WhoAmI() {
17: buttons = new JButton[names.length];
18: for(int i = 0; i < buttons.length; i++) {
19: buttons[i] = new JButton(new ImageIcon("simpson/" + names[i] + ".gif
:"));
20: buttons[i].setActionCommand(names[i]);
21: buttons[i].addActionListener(this);
22: middlePanel.add(buttons[i]);
23: }
24:
25: contentPane.add(topLabel, BorderLayout.NORTH);
26: contentPane.add(bottomLabel, BorderLayout.SOUTH);
27: contentPane.add(middlePanel);
28: setWho();
29: topLabel.setText("Who is " + who + "?");
30: bottomLabel.setText("Num of trials : " + trial + " " + "Correct answ
:ers : " + correct );
31: }
32:
33: public void setWho() {
34: who = names[(int)(names.length*Math.random())];
35: }
36:
37: public void actionPerformed(ActionEvent e) {
38: if(e.getActionCommand().equals(who)) {
39: correct++;
40: trial++;
41: setWho();
42: topLabel.setText("You are right! Next question: who is " + who + "?"
:);
43: } else {
44: trial++;
45: setWho();
46: topLabel.setText("You are wrong! Next question: who is " + who + "?"
:);
47: }
48: bottomLabel.setText("Num of trials : " + trial + " " + "Correct answ
:ers : " + correct );
49: }
50:
51: public static void main(String[] args) {
52: JFrame f = new WhoAmI();
53: f.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
54: f.setSize(280,180);
55: f.setVisible(true);
56: }
57:}
58:
Q9)
1:import java.util.*;
2:import java.io.*;
3:
4:public class FinalScore {
5: public static void main(String[] args) throws IOException {
6: String inFile = "score.txt";
7: String outFile = "result.txt";
8: BufferedReader in = new BufferedReader(new FileReader(inFile));
9: PrintStream out = new PrintStream(new FileOutputStream(outFile));
10: StringTokenizer st = null;
11: String line = null;
12: double score = 0;
13: while((line = in.readLine()) != null) {
14: score = 0;
15: st = new StringTokenizer(line);
16: out.print(st.nextToken());
17: out.print('\t');
18: for(int i = 0; i < 5; i++) {
19: score+=0.6*Double.parseDouble(st.nextToken());
20: }
21: score+=0.5*Double.parseDouble(st.nextToken());
22: score+=0.45*Double.parseDouble(st.nextToken());
23: out.println(score);
24: }
25:
26: }
27:}