gradessort.java

是<java程序设计>的课后作业2-8源码.可以供初学者参考,作了解java基础语法所用.

/**
 * @(#)GradesSort.java
 *
 *
 * @author 
 * @version 1.00 2009/3/17
 */
import javax.swing.JOptionPane;

public class GradesSort {
        
        

    /**
     * Creates a new instance of <code>GradesSort</code>.
     */
    public GradesSort() {
    }
    
    public static void studentGradeSort(student[] studentList)
    {
        for(int i=studentList.length-1;i>0;i--)            		
           {
             student maxStudent=new student();
              //maxStudent.studentName=studentList[0].studentName;
              //maxStudent.grade=studentList[0].grade;
              int max=0;
              for(int j=1;j<=i;j++)
            	{
            		if(studentList[max].getGrade()<studentList[j].getGrade())
            			max=j;            			            		        		  			
            	}
            	
              if(max!=i) 
              {
              	maxStudent.setName(studentList[max].getName());
              	maxStudent.setGrade(studentList[max].getGrade());
              	
              	studentList[max].setName(studentList[i].getName());
              	studentList[max].setGrade(studentList[i].getGrade());
              	
              	studentList[i].setName(maxStudent.getName());
              	studentList[i].setGrade(maxStudent.getGrade());  
              }           
              
            	
            }
    }
    
    /**
     * @param args the command line arguments
     */
    public static void main(String[] args) {
        // TODO code application logic here
        
        //提示用户输入学生数量
        String strStudentNumber=JOptionPane.showInputDialog(null,
        "请输入需要登记的学生数量(如,10):\n","Exercise 5.16 Input",JOptionPane.QUESTION_MESSAGE);
        
        //转化为整型
        int studentNumber=Integer.parseInt(strStudentNumber);
        
        //创建student型的数组
        student[] studentGradeList=new student[studentNumber];
        
        //这句话太重要了!!!
        //我调了三个小时啊!!!
        //每个对象必须显式初始化
        for(int i=0;i<studentGradeList.length;i++)
        	studentGradeList[i]=new student();
        
        //接受输入
        for(int i=0;i<studentNumber;i++)
        {
        	//输入姓名
        	String strStudentName=JOptionPane.showInputDialog(null,"请输入第"+(i+1)+"位学生的姓名:\n","Exercise 5.16 Input",JOptionPane.QUESTION_MESSAGE);
        	studentGradeList[i].setName(strStudentName);
        	//接受成绩
        	String strStudentGrade=JOptionPane.showInputDialog(null,"请输入第"+(i+1)+"位学生的成绩:\n","Exercise 5.16 Input",JOptionPane.QUESTION_MESSAGE);
        	//转换为整型
        	double grade=Double.parseDouble(strStudentGrade);
        	studentGradeList[i].setGrade(grade);        	
        }       
        
        studentGradeSort(studentGradeList);
        
        for(int i=studentGradeList.length-1;i>=0;i--)
        {
        	System.out.println(studentGradeList[i].getName()+"  "+studentGradeList[i].getGrade());
        }
        
        
        
    }
      
}