1、【
简答题】
本题的功能是计算二维数组各个元素的和。程序中定义了二维数组arr,arr有3行4列共l2个元素,程序中采用for循环语句的嵌套来计算数组中各个元素的和,并将结果保存在sum变量中,最后打印输出结果。
public class javal{
public static void main(String[] args){
int arr[][]={{l,2,3,4},{5,6,7,8},{9,10,11,12}};
int sum=0;
int i=0,j=0;
for(i=0;
)
for(
)
;
System.OUt.println("sum="+sum);
}
}
[18分]
解析:
第1处:i<3;i++或i<=2;i++
第2处:j=O;j<4;j++或j=0;j<=3;j++
第3处:sum=sum+Arr[i][j]
2、【
简答题】
下面的程序中,有两个文本框,Input和Output,用户在Input文本框中输入字符串后回车,字符串会在Output文本框中出现。
import java.awt.*;
import java.awt.event.*;
public class java2 extends Frame{
public static void main(String args[]){
java2 f=new java2("java2");
Panel pan=new Panel();
f.init();
}
pubhc java2(String str){
super(str);
}
public void init(){
addWindowListener(new WindowAdapter(){
public void windowClosing(WindowEvent e){
System.exit(O);
}
}};
setSize(200,200);
setLayout(new FlowlLayout());
final TextField tfl=new TextField(20):
final TextField tf2=new TextField(20);
final Label hi—new Label("Input:");
final Label la2一new Label("Output:");
tfl.addActionListener(
{
public void actionPerformed(ActionEvent e){
tf2.setTex(
);
}
});
add(la1);
add(tfl);
add(la2);
add(tf2);
setVisible(true);
}
}
[24分]
解析:
第1处:nEw ACtionListEnEr()
第2处:tFl.GEtTExt()
3、【
简答题】
本题的功能是对图形进行操作,包括旋转、移位、放大和剪切。窗口中有4个单选按钮和一个图形面板,图形面板中有一个矩形和该矩形移位操作后的图形,任选其中一个单选按钮,则图形面板中将显示该操作后的图形。
import java.awt.*;
import java.awt.event.*;
import java.awt.geom.*;
import java.util.*;
import javax.swing.*;
public class java3
{
public static void main(String[]args)
{
JFrame frame=new TransformTestFrame();
frame.setDefaultCloseOperation(JFrame.EXIT_
0N_CLoSE);
frame.show();
}
}
class TransformTest extends JFrame
{
public TransformTestFrame()
{
setTitle("java3");
setSize(WIDTH,HEIGHT);
Container contentPane=getContentPane();
canvas=new TransformPanel();
contentPane.add(canvas,BorderLayout.CEN-
TER);
JPanel buttonPanel=new JPanel():
ButtonGroup group=new ButtonGroup();
JRadioButton rotateButton
=new JRadioButton("旋转",true);
buttonPanel.add(rotateButton);
group.add(rotateButton);
rotateButton.addActionListener(new
ActionListener()
{
public void actionPerformed(ActionEvent event)
{
canvas.setRotate();
}
});
JRadioButton trans|ateButton
=new JRadioButton("移位",false);
buttonPanel.add(translateButton);
group.add(translateButton);
translateButton.addActionListener(new
ActionLiatener()
public void actionPerformed(ActionEvent event)
{
canvas.setTranslate();
}
});
JRadioButton scaleButton
=new JRadioButton("放大",false);
buttonPanel.add(scaleButton):
group.add(scaleButton);
scaleButton.addActionListener(new
ActionListener()
{
public void actionPerformed(ActionEvent event)
{
canvas.setScale();
}
});
JRadioButton shearButton
=new JRadioButton("剪切",false);
buttonPanel.add(shearButton):
group.add(shearButton);
shearButton.addActionListener(new
ActionListener()
{
public void actionPerformed(ActionEvent event)
{
canvas.setShear();
}
});
contentPane.add(buttonPanel,BorderLayout.
NORTH):
}
private TransformPanel canvas;
private static final int WIDTH=300;
private static final int HEIGHT=300;
}
class TransformPanel extend JPanel
{
public TransformPanel()
{
square=new Rectangle2D.Double(-50,-50,
100,100);
t = new AffineTransform();
setRotate();
}
public void paintComponent()
{
super.paintComponent(g);
Graphics2D g2=(Graphies2D)g;
g2.translate(getWidth()/2,getHeight()/2):
g2.setPaint(Color.gray);
g2.draw(square);
g2.transform(t);
g2.setPaint(Color.black);
g2.draw(square);
}
public void setRotate()
{
t.setToRotation(Math.toRadians(30));
repaint();
}
public void setTranslate()
{
t.setToTranslation(20,1 5);
repaint();
}
public void setScale()
{
t.setToScale(2.0,1.5):
repaint();
}
public void setShear()
{
t.setToShear(-0.2,O);
repaint();
}
private Rectangle2D square;
private AffineTransform t;
}
[18分]
解析:
第1处:ClAss TrAnsFormTEstFrAmE ExtEnDs JFrAmE
第2处:ClAss TrAnsFormPAnEl ExtEnDs JFrAmE
第3处:puBliC voiD pAintComponEnt(GrAphiCs G)