录入学生成绩，按平均分输出 - 黑马程序员技术交流社区

package test_treeSet;
import java.util.Comparator;
import java.util.Scanner;
import java.util.TreeSet;
public class StudentDemo {
/**
* 键盘录入3个学生成绩，按总分高低输出
*/
public static void main(String[] args) {
// TODO Auto-generated method stub
//建立TreeSet集合，可自定义比较器，保证元素唯一和排序
TreeSet<Student> ts = new TreeSet<Student>(new Comparator<Student>(){
@Override
public int compare(Student s1, Student s2) {
// int result = (int)(s1.getTotal() - s2.getTotal());//学生总分比较
int result = (int)(s1.getAverage() - s2.getAverage());//平均分排序
result = (int)(result==0?s1.getChinese()-s2.getChinese():result);
result = (int)(result==0?s1.getMath()-s2.getMath():result);
result = (int)(result==0?s1.getEnglish()-s2.getEnglish():result);
if(result==0){
result = s1.getName().compareTo(s2.getName());
}
return result;
}
});
for (int i = 1; i < 4; i++) {
System.out.println("请输入第"+i+"个学生的成绩，格式为：姓名语文数学英语：");
String str = new Scanner(System.in).nextLine();
String[] s = str.split("\\s+");//正则表达式切割字符串至少一个空格
Student s1 = new Student(s[0],Double.parseDouble(s[1]), Double.parseDouble(s[2]),
Double.parseDouble(s[3]));
ts.add(s1);
}
//遍历输出学生信息
System.out.println("姓名\t语文\t数学\t英语\t总分\t平均分");
for(Student s:ts){
System.out.println(s.getName()+"\t"+s.getChinese()+"\t"+s.getMath()+
"\t"+s.getEnglish()+"\t"+s.getTotal()+"\t"+s.getAverage());
}
}
}
package test_treeSet;
/**
* 创建学生类，包含姓名，语文、数学、英文成绩
* */
public class Student {
private String name;
private double chinese;
private double math;
private double english;
public String getName() {
return name;
}
public Student(String name, double chinese, double math, double english) {
super();
this.name = name;
this.chinese = chinese;
this.math = math;
this.english = english;
}
public void setName(String name) {
this.name = name;
}
public double getChinese() {
return chinese;
}
public void setChinese(double chinese) {
this.chinese = chinese;
}
public double getMath() {
return math;
}
public void setMath(double math) {
this.math = math;
}
public double getEnglish() {
return english;
}
public void setEnglish(double english) {
this.english = english;
}
//获取总分数
public double getTotal(){
return chinese + math + english ;
}
//获取平均分
public double getAverage(){
return this.getTotal()/3;
}
}

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