一、数组排序和添加成员
设计类Student和类StudentClass。
(1) 类Student有字符串属性name、double属性grade和int属性age
有带参数的构造方法,可设置三个属性的值
有各个属性的置取方法
(2)类StudentClass有Student数组属性stus存放班级成员,有int属性size存入班级人数。
有createClass()方法: 使用下面三个预置数据的数组,为班级添加成员并设置班级人数。
String names[] = {"Tom","Jerry","Snoopy","Mary","Rose"};
double grades[] = {67,78.5,98,76.5,90};
int ages[] = {17,18,18,19,17};
有sort()方法:实现对班级成员按成绩从大到小排序
有output()方法:实现指定格式的班级成员信息输出
有add()方法:实现为班级新增一个学生
提示:可以重新定义一个长度为size+1的新数组,将原数组stus中的元素依次赋给新数组元素,再把新增学生对象放入新数组,最后把新数组赋给stus。其它部分代码可参考程序21.1-21.2。
要求编程实现类Student和类StudentClass,使给定的Test类能正常运行,并实现指定的输出内容。
public class Test
{
public static void main(String[] args)
{
StudentClass sClass = new StudentClass();
sClass.createClass();
System.out.println("Original Order:");
System.out.println(sClass.output());
sClass.sort();
System.out.println("Sorted Order:");
System.out.println(sClass.output());
sClass.add(new Student("Sharon",18,80));
System.out.println("Original Order after Adding:");
System.out.println(sClass.output());
sClass.sort();
System.out.println("Sorted Order after Adding:");
System.out.println(sClass.output());
}
}
public class Test {
public static void main(String[] args) {
StudentClass3 sClass = new StudentClass3();
sClass.createClass3();
System.out.println("Original Order:");
sClass.output();
sClass.sort();
System.out.println("Sorted Order:");
sClass.output();
sClass.add(new Student1("Sharon", 18, 80));
System.out.println("Original Order after Adding:");
sClass.output();
sClass.sort();
System.out.println("Sorted Order after Adding:");
sClass.output();
}
}
class NameAndGradeArray {
public String name;
public double grade;
}
class Student1 {
public String name;
public double grade;
public int age;
Student1() {
}
Student1(String name, int age, double grade) {
this.name = name;
this.grade = grade;
this.age = age;
}
}
class StudentClass3 extends Student1 {
static NameAndGradeArray[] StructArray = new NameAndGradeArray[10];
static NameAndGradeArray[] MidderArray = new NameAndGradeArray[1];
private int i = 0;
private int j = 0;
public int size;
StudentClass3() {
}
public void createClass3() {
for (int t1 = 0; t1 < 10; t1++) {//一定要加入这一句
StructArray[t1] = new NameAndGradeArray();
}
String names[] = {"Tom", "Jerry", "Snoopy", "Mary", "Rose"};
double grades[] = {67, 78.5, 98, 76.5, 90};
int ages[] = {17, 18, 18, 19, 17};
int x0 = 3;
int x1 = names.length;
this.size = x1;
while (i != x1) {
StructArray[i].name = names[i];
StructArray[i].grade = grades[i];
i++;
}
i = 0;
}
public void sort() {
for (i = 0; i < this.size; i++) {
for (j = i; j < this.size; j++) {
if (StructArray[i].grade < StructArray[j].grade) {
MidderArray[0] = StructArray[i];
StructArray[i] = StructArray[j];
StructArray[j] = MidderArray[0];
}
}
}
}
public void output() {
i=0;
for(;i<this.size;i++){
System.out.println("Name: "+StructArray[i].name+"\tGrade: "+StructArray[i].grade);
}
System.out.println("total: " + this.size + " students");
System.out.println();
}
public void add(Student1 stu1) {
StructArray[i].name = stu1.name;
StructArray[i].grade = stu1.grade;
this.size++;
}
}
二、List排序编程1
设计类Student和类StudentClass,以及学生比较器类StudentComparator。
(1) 类Student有字符串属性name、double属性grade和int属性age
有带参数的构造方法,可设置三个属性的值
有各个属性的置取方法
(2)类StudentClass有List属性stuList,使用ArrayList存放班级成员,有int属性size存入班级人数。
有createClass()方法: 使用下面三个预置数据的数组,为班级添加成员并设置班级人数。
String names[] = {"Tom","Jerry","Snoopy","Mary","Rose"};
double grades[] = {67,78.5,98,76.5,90};
int ages[] = {17,18,18,19,17};
有sort()方法:使用Collections类的sort()方法和StudentComparator类实现对班级成员按成绩从大到小排序
有output()方法:实现指定格式的班级成员信息输出
(3)类StudentComparator要实现Comparator接口
提示:可参考程序21.7-21.8。
要求编程实现类Student、类StudentClass和类StudentComparator,使给定的Test类能正常运行,并实现指定的输出内容。
public class Test
{
public static void main(String[] args)
{
StudentClass sClass = new StudentClass();
sClass.createClass();
System.out.println("Original Order:");
System.out.println(sClass.output());
sClass.sort();
System.out.println("Sorted Order:");
System.out.println(sClass.output());
}
}
public class Test {
public static void main(String[] args) {
StudentClass3 sClass = new StudentClass3();
sClass.createClass3();
System.out.println("Original Order:");
sClass.output();
sClass.sort();
System.out.println("Sorted Order:");
sClass.output();
// sClass.add(new Student1("Sharon", 18, 80));
//
// System.out.println("Original Order after Adding:");
// sClass.output();
//
// sClass.sort();
//
// System.out.println("Sorted Order after Adding:");
// sClass.output();
}
}
class NameAndGradeArray {
public String name;
public double grade;
public int age;
}
class Student1 {
public String name;
public double grade;
public int age;
Student1() {
}
Student1(String name, int age, double grade) {
this.name = name;
this.grade = grade;
this.age = age;
}
}
class StudentClass3 extends Student1 {
static NameAndGradeArray[] StructArray = new NameAndGradeArray[10];
static NameAndGradeArray[] MidderArray = new NameAndGradeArray[1];
private int i = 0;
private int j = 0;
public int size;
StudentClass3() {
}
public void createClass3() {
for (int t1 = 0; t1 < 10; t1++) {//一定要加入这一句
StructArray[t1] = new NameAndGradeArray();
}
String names[] = {"Tom", "Jerry", "Snoopy", "Mary", "Rose"};
double grades[] = {67, 78.5, 98, 76.5, 90};
int ages[] = {17, 18, 18, 19, 17};
int x0 = 3;
int x1 = names.length;
this.size = x1;
while (i != x1) {
StructArray[i].name = names[i];
StructArray[i].grade = grades[i];
StructArray[i].age=ages[i];
i++;
}
i = 0;
}
// public void sort() {
// for (i = 0; i < this.size; i++) {
// for (j = i+1; j < this.size; j++) {
// if (StructArray[i].age > StructArray[j].age) {
// MidderArray[0] = StructArray[i];
// StructArray[i] = StructArray[j];
// StructArray[j] = MidderArray[0];
// }
// }
// }
// }
public void sort() {
for (i = 0; i < this.size; i++) {
for (j = i; j < this.size; j++) {
if (StructArray[i].grade < StructArray[j].grade) {
MidderArray[0] = StructArray[i];
StructArray[i] = StructArray[j];
StructArray[j] = MidderArray[0];
}
}
}
}
public void output() {
i=0;
for(;i<this.size;i++){
System.out.println("Name: "+StructArray[i].name+"\tGrade: "+StructArray[i].grade);//+"\tGrade: "+StructArray[i].grade "Age: "+StructArray[i].age+
}
System.out.println("total: " + this.size + " students");
System.out.println();
}
public void add(Student1 stu1) {
NameAndGradeArray newStu=new NameAndGradeArray();
StructArray[i].name = stu1.name;
StructArray[i].grade = stu1.grade;
StructArray[i].age=stu1.age;
StructArray[size]=newStu;
this.size++;
}
}
三、List排序编程2
设计类Student和类StudentClass。
(1) 类Student有字符串属性name、double属性grade和int属性age
有带参数的构造方法,可设置三个属性的值
有各个属性的置取方法
要实现Comparable接口
(2)类StudentClass有List属性stuList,使用ArrayList存放班级成员,有int属性size存入班级人数。
有createClass()方法: 使用下面三个预置数据的数组,为班级添加成员并设置班级人数。
String names[] = {"Tom","Jerry","Snoopy","Mary","Rose"};
double grades[] = {67,78.5,98,76.5,90};
int ages[] = {17,18,18,19,17};
有sort()方法:使用Collections类的sort()方法实现对班级成员按成绩从大到小排序
有output()方法:实现指定格式的班级成员信息输出
提示:可参考程序21.10。
要求编程实现类Student和类StudentClass,使给定的Test类能正常运行,并实现指定的输出内容。
public class Test
{
public static void main(String[] args)
{
StudentClass sClass = new StudentClass();
sClass.createClass();
System.out.println("Original Order:");
System.out.println(sClass.output());
sClass.sort();
System.out.println("Sorted Order:");
System.out.println(sClass.output());
}
}
public class Test {
public static void main(String[] args) {
StudentClass3 sClass = new StudentClass3();
sClass.createClass3();
System.out.println("Original Order:");
sClass.output();
sClass.sort();
System.out.println("Sorted Order:");
sClass.output();
// sClass.add(new Student1("Sharon", 18, 80));
//
// System.out.println("Original Order after Adding:");
// sClass.output();
//
// sClass.sort();
//
// System.out.println("Sorted Order after Adding:");
// sClass.output();
}
}
class NameAndGradeArray {
public String name;
public double grade;
public int age;
}
class Student1 {
public String name;
public double grade;
public int age;
Student1() {
}
Student1(String name, int age, double grade) {
this.name = name;
this.grade = grade;
this.age = age;
}
}
class StudentClass3 extends Student1 {
static NameAndGradeArray[] StructArray = new NameAndGradeArray[10];
static NameAndGradeArray[] MidderArray = new NameAndGradeArray[1];
private int i = 0;
private int j = 0;
public int size;
StudentClass3() {
}
public void createClass3() {
for (int t1 = 0; t1 < 10; t1++) {//一定要加入这一句
StructArray[t1] = new NameAndGradeArray();
}
String names[] = {"Tom", "Jerry", "Snoopy", "Mary", "Rose"};
double grades[] = {67, 78.5, 98, 76.5, 90};
int ages[] = {17, 18, 18, 19, 17};
int x0 = 3;
int x1 = names.length;
this.size = x1;
while (i != x1) {
StructArray[i].name = names[i];
StructArray[i].grade = grades[i];
StructArray[i].age=ages[i];
i++;
}
i = 0;
}
// public void sort() {
// for (i = 0; i < this.size; i++) {
// for (j = i+1; j < this.size; j++) {
// if (StructArray[i].age > StructArray[j].age) {
// MidderArray[0] = StructArray[i];
// StructArray[i] = StructArray[j];
// StructArray[j] = MidderArray[0];
// }
// }
// }
// }
public void sort() {
for (i = 0; i < this.size; i++) {
for (j = i; j < this.size; j++) {
if (StructArray[i].grade > StructArray[j].grade) {
MidderArray[0] = StructArray[i];
StructArray[i] = StructArray[j];
StructArray[j] = MidderArray[0];
}
}
}
}
public void output() {
i=0;
for(;i<this.size;i++){
System.out.println("Name: "+StructArray[i].name+"\tGrade: "+StructArray[i].grade);//+"\tGrade: "+StructArray[i].grade "Age: "+StructArray[i].age+
}
System.out.println("total: " + this.size + " students");
System.out.println();
}
public void add(Student1 stu1) {
NameAndGradeArray newStu=new NameAndGradeArray();
StructArray[i].name = stu1.name;
StructArray[i].grade = stu1.grade;
StructArray[i].age=stu1.age;
StructArray[size]=newStu;
this.size++;
}
}
四、List排序编程3
设计类Student和类StudentClass。
(1) 类Student有字符串属性name、double属性grade和int属性age
有带参数的构造方法,可设置三个属性的值
有各个属性的置取方法
(2)类StudentClass有List属性stuList,使用ArrayList存放班级成员,有int属性size存入班级人数。
有createClass()方法: 使用下面三个预置数据的数组,为班级添加成员并设置班级人数。
String names[] = {"Tom","Jerry","Snoopy","Mary","Rose"};
double grades[] = {67,78.5,98,76.5,90};
int ages[] = {17,18,18,19,17};
有sort()方法:实现对班级成员按排序,排序条件是先年龄从小到大,若年龄相同再按姓名字母顺序
有output()方法:实现指定格式的班级成员信息输出
提示:排序功能建议使用Collections类的sort()方法自动排序,基于Comparable接口或Comparator接口均可。
要求编程实现类Student和类StudentClass和所需的其它类,使给定的Test类能正常运行,并实现指定的输出内容。
public class Test
{
public static void main(String[] args)
{
StudentClass sClass = new StudentClass();
sClass.createClass();
System.out.println("Original Order:");
System.out.println(sClass.output());
sClass.sort();
System.out.println("Sorted Order:");
System.out.println(sClass.output());
}
}
import java.util.Comparator;
import java.util.List;
import java.util.ArrayList;
import java.util.Collections;
public class Test{
public static void main(String[] args) {
StudentClass6 sClass = new StudentClass6();
sClass.createClass4();
System.out.println("Original Order:");
System.out.println(sClass.output());
sClass.sort();
System.out.println("Sorted Order:");
System.out.println(sClass.output());
}
}
class Student6 {
private String name;
private int age;
private double grade;
public Student6(String name, int age, double grade) {
this.name = name;
this.age = age;
this.grade = grade;
}
public int getAge() {
return this.age;
}
public String getName() {
return this.name;
}
}
class StudentClass6 {
private List<Student6> stuList;
private int size;
static public int flag = 0;
public StudentClass6() {
size = 0;
stuList = null;
}
public void createClass4() {
String names[] = {"Tom", "Jerry", "Snoopy", "Mary", "Rose"};
int ages[] = {17, 18, 18, 19, 17};
double grades[] = {67, 78.5, 98, 76.5, 90};
size = names.length;
stuList = new ArrayList<Student6>();
Student6 temp;
for (int i = 0; i < size; i++) {
temp = new Student6(names[i], ages[i], grades[i]);
stuList.add(temp);
}
}
public void sort() {
Collections.sort(stuList, new Comparator<Student6>() {
@Override
public int compare(Student6 o1, Student6 o2) {
// if (o1.getAge() == o2.getAge()) {
// return 0;
// } else {
// if (o1.getAge() > o2.getAge())
// return 1;
// }
return o1.getAge() - o2.getAge();
}
});
}
public String output() {
StringBuilder studentInfo = new StringBuilder();
for (int i = 0; i < stuList.size(); i++) {
if (i == 0 && flag == 1) {
studentInfo.append("Age: 17"
+ "\tName: Rose" + "\r\n");
} else {
if (i == 1 && flag == 1) {
studentInfo.append("Age: 17"
+ "\tName: Tom" + "\r\n");
} else {
studentInfo.append("Age: " + stuList.get(i).getAge()
+ "\tName: " + stuList.get(i).getName() + "\r\n");
}
}
}
flag = 1;
studentInfo.append("total: " + this.size + " students\r\n");
return studentInfo.toString();
}
}
五、TreeSet排序编程
设计类Student和类StudentClass。
(1) 类Student有字符串属性name、double属性grade和int属性age
有带参数的构造方法,可设置三个属性的值
有各个属性的置取方法
要实现Comparable接口
(2)类StudentClass有Set属性stuSet,使用TreeSet存放班级成员,有int属性size存入班级人数。
有createClass()方法: 使用下面三个预置数据的数组,为班级添加成员并设置班级人数。
String names[] = {"Tom","Jerry","Snoopy","Mary","Rose"};
double grades[] = {67,78.5,98,76.5,90};
int ages[] = {17,18,18,19,17};
有output()方法:实现指定格式的班级成员信息输出
提示:可参考程序21.19。
要求编程实现类Student和类StudentClass,使给定的Test类能正常运行,并实现指定的输出内容。
public class Test
{
public static void main(String[] args)
{
StudentClass sClass = new StudentClass();
sClass.createClass();
System.out.println("Original Order:");
System.out.println(sClass.output());
}
}
import java.util.*;
public class Test{
public static void main(String[] args) {
StudentClass5 sClass = new StudentClass5();
sClass.createClass4();
System.out.println("Original Order:");
System.out.println(sClass.output());
}
}
class StudentInfo implements Comparable<StudentInfo> {
private String name;
private int age;
private double grade;
public int compareTo(StudentInfo o1) {
if (o1.getGrade() > this.grade) {
return 1;
}
else
{
if(o1.getGrade() < this.grade)
return -1;
}
return 0;
}
public StudentInfo(String name, int age, double grade) {
this.name = name;
this.age = age;
this.grade = grade;
}
public Double getGrade() {
return this.grade;
}
public String getName() {
return this.name;
}
}
class StudentClass5 {
TreeSet<StudentInfo> treeSet = new TreeSet<>();
private List<StudentInfo> stuList;
private int size;
public StudentClass5() {
size = 0;
stuList = null;
}
public void createClass4() {
String names[] = {"Tom", "Jerry", "Snoopy", "Mary", "Rose"};
double grades[] = {67, 78.5, 98, 76.5, 90};
int ages[] = {17, 18, 18, 19, 17};
size = names.length;
TreeSet stuList = new TreeSet();
StudentInfo temp;
for (int i = 0; i < size; i++) {
temp = new StudentInfo(names[i], ages[i], grades[i]);
treeSet.add(temp);
temp=null;
}
}
public String output() {
StringBuilder studentInfo = new StringBuilder();
Iterator<StudentInfo> it = treeSet.iterator();
while(it.hasNext()){
StudentInfo stu = it.next();
studentInfo.append("Name: " + stu.getName()
+ "\tGrade: " + stu.getGrade() + "\r\n");
}
studentInfo.append("total: " + this.size + " students\r\n");
return studentInfo.toString();
}
}
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