首页 > 代码库 > 第三题 有如下Student 对象, private String name; private int age; private int score; private String classNum; 其中,classNum 表示学生的班号,例如“class05”。 有如下List List list = new ArrayList();

第三题 有如下Student 对象, private String name; private int age; private int score; private String classNum; 其中,classNum 表示学生的班号,例如“class05”。 有如下List List list = new ArrayList();

list.add(new Student(“Tom”, 18, 100, “class05”));  

list.add(new Student(“Jerry”, 22, 70, “class04”)); 

list.add(new Student(“Owen”, 25, 90, “class05”)); 

list.add(new Student(“Jim”, 30,80 , “class05”)); 

list.add(new Student(“Steve”, 28, 66, “class06”));

 list.add(new Student(“Kevin”, 24, 100, “class04”)); 

在这个list 的基础上,完成下列要求: 

1) 计算所有学生的平均年龄

2) 计算各个班级的平均分 

package com.hanqi.test;public class Student {     private String name;          private int age;          private int score;      private String classNum;            public String getName() {        return name;    }    public void setName(String name) {        this.name = name;    }    public int getAge() {        return age;    }    public void setAge(int age) {        this.age = age;    }    public int getScore() {        return score;    }    public void setScore(int score) {        this.score = score;    }    public String getClassNum() {        return classNum;    }    public void setClassNum(String classNum) {        this.classNum = classNum;    }    public Student() {        super();            }    public Student(String name, int age, int score, String classNum) {        super();        this.name = name;        this.age = age;        this.score = score;        this.classNum = classNum;    }    }
package com.hanqi.test;import java.util.ArrayList;import java.util.List;public class TestStudent {    public static void main(String[] args) {                List<Student>  list = new ArrayList<>();                list.add(new Student("Tom",18,100,"class05"));        list.add(new Student("Jerry",22,70,"class04"));        list.add(new Student("Owen",25,90,"class05"));        list.add(new Student("Jim",30,80,"class05"));        list.add(new Student("Steve",28,66,"class06"));        list.add(new Student("Kevin",24,100,"class04"));                        int sum=0;        for(int i=0;i<list.size();i++)        {            sum+=list.get(i).getAge();        }        System.out.println("所有学生的平均分是:"+sum/list.size());                int score4=0;        int score5=0;        int score6=0;        int num4=0;        int num5=0;        int num6=0;        for(int j=0;j<list.size();j++)        {        Student st=list.get(j);                if(st.getClassNum()=="class04")        {            num4++;            score4 +=st.getScore();        }        else if(st.getClassNum()=="class05")        {            num5++;            score5+=st.getScore();        }        else        {            num6++;            score6+=st.getScore();        }               }        System.out.println("class04的平均分数是:"+score4/num4);        System.out.println("class05的平均分数是:"+score5/num5);        System.out.println("class06的平均分数是:"+score6/num6);            }}

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第三题 有如下Student 对象, private String name; private int age; private int score; private String classNum; 其中,classNum 表示学生的班号,例如“class05”。 有如下List List list = new ArrayList();