Java计算机二级（上机真题）

1.
import java.io.*;
public class Java_1 {
    public static void main(String[ ] args) throws IOException {
        InputStreamReader ir;
        BufferedReader in;
        int max, x;
        String data;

        max = 0;
        ir = new InputStreamReader(System.in);
        in = new BufferedReader(ir);
        System.out.println("请输入5个正整数：");
        //*********Found**********
        for (int i = 1; i<= 5; i++) {
            data = in.readLine();
            //*********Found**********
            x = Integer.parseInt(data);
            if ( max < x )
                //*********Found**********
                max = x;
        }
        System.out.println("输入的最大值是 "+ max);
    }
}
2.文件的和递归调用
import java.io.File;

public class Java_2
{
   public static void main(String s[])
   {
      //Getting the Current Working Directory
      String curDir = System.getProperty("user.dir");
      System.out.println("当前的工作目录是:"+curDir);
		
      //*********Found**********
      File ff=new File(curDir);
      String[] files=ff.list();
      for(int i=0; i");
         String[] files=f.list();
         level++;
         //*********Found**********
         for(int i=0; i best)
        best = scores[i];
    }
 
    //求各分数的等级并显示
    for (int i=0; i= best - 10)
        grade = 'A';
      //*********Found**********
      else if (scores[i] >= best - 20)
        grade = 'B';
      else if (scores[i] >= best - 30)
        grade = 'C';
      else if (scores[i] >= best - 40)
        grade = 'D';
      else
        grade = 'F';
      System.out.println("Student " + i + " score is " + scores[i] +
        " and grade is " + grade);
    }
  }
}

2.
public class Java_2 {
    public static void main(String[ ] args) {
        Point pt;
        //*********Found**********
        pt = new Point(2, 3);
        System.out.println(pt);
    }
}

class Point {

    //*********Found**********
    private int x;
    private int y;

    //*********Found**********
    public Point (int a, int b) {
        x = a;
        y = b;
    }

    int getX( ) {
        return x;
    }

    int getY( ) {
        return y;
    }

    void setX(int a) {
        x = a;
    }

    void setY(int b) {
        y = b;
    }

    //*********Found**********
    public String toString ( ) {
        return "( " + x + "," + y + " ) ";
    }
}

3.
import java.awt.*;
import java.awt.event.*;    
//*********Found**********
import javax.swing.*;
   
//*********Found**********
public class Java_3 extends JPanel{     
   
  private int counter = 0;    
   
  private JButton closeAllButton;    
   
  public Java_3() {    
    JButton newButton = new JButton("New");    
    //*********Found**********
    add(newButton);
    newButton.addActionListener(new ActionListener(){
      public void actionPerformed(ActionEvent evt){
        CloseFrame f = new CloseFrame();    
        counter++;    
        f.setTitle("窗体 " + counter);    
        f.setSize(200, 150);    
        f.setLocation(30 * counter, 30 * counter);    
        //*********Found**********
        f.setVisible(true);    
        closeAllButton.addActionListener(f); 
      }  
    });
        
    closeAllButton = new JButton("Close all");    
    add(closeAllButton);    
  }      
   
  public static void main(String[ ] args) {    
    JFrame frame = new JFrame();    
    frame.setTitle("多窗体测试");    
    frame.setSize(300, 200);    
    frame.addWindowListener(new WindowAdapter() {    
      public void windowClosing(WindowEvent e) {    
        System.exit(0);    
      }    
    });    
   
    Container contentPane = frame.getContentPane();    
    contentPane.add(new Java_3());   
  
    frame.setVisible(true) ;    
  } 
} 
   
//*********Found**********
class CloseFrame extends JFrame implements ActionListener {    
  public void actionPerformed(ActionEvent evt) {     
    setVisible(false);    
  }    
}

1.矩阵运算
public class Java_1 {

    public static void main(String args[]) {
        int a[][] = {{2, 3, 4}, {4, 6, 5}};
        int b[][] = {{1, 5, 2, 8}, {5, 9, 10, -3}, {2, 7, -5, -18}};
        int c[][] = new int[2][4];
        for (int i = 0; i < 2; i++) {
            for (int j = 0; j < 4; j++) {
                //*********Found********
                c[i][j] = 0 ;
                //*********Found********
                for (int k = 0; k < 3; k++) 
                    //*********Found********
                    c[i][j] += a[i][k]*b[k][j];
                System.out.print(c[i][j] + "  ");
            }
            System.out.println();
        }
    }
}