【java】定义课程信息;继承和组合练习
作者:互联网
- 问题:
定义课程信息类,包含课程编号、课程名称及学生成绩。编程实现对软件工程专业的某班级的所有课程成绩统计,包括平均成绩、最高成绩、最低成绩,并打印成绩等级分布律。
分析
初分析:
父类(课程信息类):三个变量(编号、名称、以及学生成绩)、构造方法默认以及全选的、方法get个set类和display。
子类(对父类的统计及分析):构造方法(关键字super()),方法(平均值、最大最小值以及分布律)
设计
父类(课程信息类):
package HOME8;
public class Course_infor {
private String number;
private String name;
public int[] grades;
public Course_infor() {
}
public Course_infor(String number, String name, int[] grades ) {
this.number = number;
this.name = name;
this.grades = grades;
}
public String getNumber() {
return number;
}
public void setNumber(String number) {
this.number = number;
}
public String getName() {
return name;
}
public void setName(String name) {
this.name = name;
}
public int[] getGrades() {
return grades;
}
public void setGrades(int[] grades) {
this.grades = grades;
}
public void display() {
System.out.println("课程编号:"+number+"\n"+ "课程名称:"+name+"\n");
}
}
子类(对父类的统计及分析)
package HOME8;
public class Statistics extends Course_infor {
int sum = 0,Max,Min;
int[] DL = new int[11];
public Statistics() {
}
public Statistics(String number, String name, int[] grades ) {
super(number,name,grades);
Min = grades[0];
Max = grades[0];
}
public void average() {
for(int i = 0;i<grades.length;i++) {
sum += grades[i];
}
System.out.println("平均值:"+(double)sum/grades.length+"\n");
}
public void Maxgrades() {
for(int i = 0;i<grades.length;i++) {
if(Max<grades[i])
{
Max = grades[i];
}
}
System.out.println("最大值:"+Max+"\n");
}
public void Mingrades() {
for(int i = 0;i<grades.length;i++) {
if(Min>grades[i])
{
Min = grades[i];
}
}
System.out.println("最小值:"+Min+"\n");
}
public void DL() {
for(int i = 0;i<grades.length;i++) {
DL[grades[i]/10]++;
}
for(int i=0;i<11;i++) {
System.out.printf("%d~%d:",10*i,10*(i+1));
for(int j = 0;j<DL[i];j++) {
System.out.printf("*");
}
System.out.println();
}
}
}
测试
测试
点击查看代码
package HOME8;
public class test {
public static void main(String[] args) {
Course_infor a = new Course_infor("a","软件工程实践",new int[]{12,14,1,2,21,22,33,44,55,66,77,88,99});
a.display();
Statistics b = new Statistics("a","软件工程实践",new int[]{12,14,1,2,21,22,33,44,55,66,77,88,99});
b.average();
b.Maxgrades();
b.Mingrades();
b.DL();
}
}
标签:java,name,int,练习,number,grades,课程,public,String 来源: https://www.cnblogs.com/zhujiaozhu/p/15385273.html