继承分析--综合案例

学生类

• 建立一个人类（Person）和学生类（Student），功能要求如下：
  • Person类中包含4个私有型的数据成员name、addr、sex、age，分别为字符串型、字符串型、字符型、整型，表示姓名姓名、地址、性别、年龄。一个4参构造方法、一个2参构造方法、一个无参构造方法，一个输出方法显示4种属性
  • Student类继承Person类，并增加成员math、english存放数学和英语成绩，一个6参构造方法、一个2参构造方法、一个无参构造方法和覆写输出方法用于显示6种属性

class Person {
  private String name;
  private String addr;
  private char sex;
  private int age;
  public Person() {}
  public Person(String name, String addr) {
    this(name, addr, '男', 0);
  }
  public Person(String name, String addr, char sex, int age) {
    this.name = name;
    this.addr = addr;
    this.sex = sex;
    this.age = age;
  }
  public String getInfo() {
    return "姓名：" + this.name + "、地址：" + this.addr + "、性别：" + this.sex + "、年龄：" + this.age;
  }
  public void setName(String name) {
    this.name = name;
  }
  public void setAddr(String addr) {
    this.addr = addr;
  }
  public void setSex(char sex) {
    this.sex = sex;
  }
  public void setAge(int age) {
    this.age = age;
  }
public String getName() {
    return this.name;
  }
  public String getAddr() {
    return this.addr;
  }
  public char getSex() {
    return this.sex;
  }
  public int getAge() {
    return this.age;
  }
}
class Student extends Person {
  private double math;
  private double english;
  public Student() {}
  public Student(String name, String addr) {
    super(name, addr);
  }
  public Student(String name, String addr, char sex, int age, double math, double english) {
    super(name, addr, sex, age);
    this.math = math;
    this.english = english;
  }
  public String getInfo() {
    return super.getInfo() + "、数学成绩：" + this.math + "、英语成绩：" + this.english;
  }
  public void setMath(double math) {
    this.math = math;
  }
  public void setEnglish(double english) {
    this.english = english;
  }
  public double getMath() {
    return this.math;
  }
  public double getEnglish() {
    return this.english;
  }
}
public class JavaDemo {
  public static void main(String args []) {
    Student stu = new Student("张三", "天安门", '男', 12, 78.99, 89.98);
    System.out.println(stu.getInfo());
  }
}

管理人员与职员

• 定义员工类，具备姓名、年龄、性别属性，并具有构造方法和显示数据方法，定义管理层类继承员工类，并且拥有自己的属性职务和年薪，定义职员类继承员工类，并有自己的属性所属部门和月薪

class Employee {
  private String name;
  private int age;
  private String sex;
  public Employee() {}
  public Employee(String name, int age, String sex) {
    this.name = name;
    this.age = age;
    this.sex = sex;
  }
  public String getInfo() {
    return "姓名：" + this.name + "、年龄：" + this.age + "、性别：" + this.sex;
  }
  public void setName(String name) {
    this.name = name;
  }
  public void setAge(int age) {
    this.age = age;
  }
  public void setSex(String sex) {
    this.sex = sex;
  }
  public String getName() {
    return this.name;
  }
  public int getAge() {
    return this.age;
  }
  public String getSex() {
    return this.sex;
  }
}
class Manager extends Employee {
  private String job;
  private double income;
  public Manager() {}
  public Manager(String name, int age, String sex, String job, double income) {
    super(name, age, sex);
    this.job = job;
    this.income = income;
  }
  public String getInfo() {
    return "【管理层】" + super.getInfo() + "、职位：" + this.job + "、年薪：" + this.income;
  }
  public void setJob(String job) {
    this.job = job;
  }
  public void setIncome(double income) {
    this.income = income;
  }
  public String getJob() {
    return this.job;
  }
  public double getIncome() {
    return this.income;
  }
}
class Staff extends Employee {
  private String dept;
  private double salary;
  public Staff() {}
  public Staff(String name, int age, String sex, String dept, double salary) {
    super(name, age, sex);
    this.dept = dept;
    this.salary = salary;
  }
  public String getInfo() {
    return "【职员】" + super.getInfo() + "、部门：" + this.dept + "、月薪：" + this.salary;
  }
  public void setDept(String dept) {
    this.dept = dept;
  }
  public void setSalary(double salary) {
    this.salary = salary;
  }
  public String getDept() {
    return this.dept;
  }
  public double getSalary() {
    return this.salary;
  }
}
public class JavaDemo {
  public static void main(String args []) {
    Manager man = new Manager("张三", 38, "女", "主管", 150000.00);
    Staff staff = new Staff("李四", 18, "男", "出纳", 3000.00);
    System.out.println(man.getInfo());
    System.out.println(staff.getInfo());
  }
}

字符串统计

• 编写程序，统计出字符串"want you to know one thing"字母n和字母o的出现次数

//只是一个顺序的思维模式
class StringUtil {
  public static int [] count(String str) {
    int countData [] = new int [2];
    char [] data = str.toCharArray();
    for(int x = 0; x < data.length; x++) {
      if(data[x] == 'n' || data[x] == 'N') {
        countData[0]++;
      }
      if(data[x] == 'o' || data[x] == 'O') {
        countData[1]++;
      }
    }
    return countData;
  }
}
public class JavaDemo {
  public static void main(String args []) {
    String str = "want you to know one thing";
    int result [] = StringUtil.count(str);
    System.out.println("字母n的个数：" + result[0]);
    System.out.println("字母o的个数：" + result[1]);
  }
}

//继承模式
class StringUtil {
  private String content;
  public StringUtil() {}
  public StringUtil(String content) {
    this.content = content;
  }
  public String getInfo() {
    return this.getContent();
  }
  public void setContent(String content) {
    this.content = content;
  }
  public String getContent() {
    return this.content;
  }
}
class Stringcount extends StringUtil{
  private int nCount;
  private int oCount;
  public Stringcount() {}
  public Stringcount(String content) {
    super(content);
    this.countChar();
  }
  public void countChar() {
    char [] data = super.getContent().toCharArray();
    for(int x = 0; x < data.length; x++) {
      if(data[x] == 'n' || data[x] == 'N') {
        this.nCount++;
      }
      if(data[x] == 'o' || data[x] == 'O') {
        this.oCount++;
      }
    }
  }
  public String getInfo() {
    return "n的个数：" + this.nCount + "、o的个数：" + this.oCount;
  }
  public void setNCount(int nCount) {
    this.nCount = nCount;
  } 
  public void setOCount(int oCount) {
    this.oCount = oCount;
  }
  public int getNCount() {
    return this.nCount;
  }
  public int getOCount() {
    return this.oCount;
  }
}
public class JavaDemo {
  public static void main(String args []) {
    Stringcount sc = new Stringcount("want you to know one thing");
    System.out.println(sc.getInfo());
  }
}

数组操作

建立一个可以实现整型数组的操作类（Array），而后在里面可以操作的数组大小由外部决定，而后在Array类里面需要提供有数组的如下处理：进行数据的增加（如果数据满了则无法增加）、可以实现数组容量的扩充、取得数组的全部内容。
完成之后在此基础上再派生出两个子类：

• 数组排序类：返回的数据必须是排序后的结果
• 数组反转类：可以实现内容的首尾互换

class Array {
  private int [] data;
  private int foot;
  public Array() {}
  public Array(int length) {
    if(length > 0) {
      this.data = new int [length];
    } else {
      this.data = new int [1];
    }
  }
  public void increment(int num) {
    int [] newData = new int [this.data.length + num];
    System.arraycopy(this.data, 0, newData, 0, this.data.length);
    this.data = newData;
  }
  public boolean add(int num) {
    if(this.foot < this.data.length) {
      this.data[this.foot++] = num;
      return true;
    }
    return false;
  }
  public int [] getData() {
    return this.data;
  }
}
class SortArray extends Array {
  public SortArray() {}
  public SortArray(int length) {
    super(length);
  }
  public int [] getData() {
    java.util.Arrays.sort(super.getData());
    return super.getData();
  }
}
class ReverseArray extends Array {
  public ReverseArray() {}
  public ReverseArray(int length) {
    super(length);
  }
  public int [] getData() {
    int center = super.getData().length / 2;
    int head = 0;
    int tail = super.getData().length - 1;
    for(int x = 0; x < center; x++) {
      int temp = super.getData() [head];
      super.getData() [head] = super.getData() [tail];
      super.getData() [tail] = temp;
      head++;
      tail--;
    }
    return super.getData();
  }
}
public class JavaDemo {
  public static void main(String args []) {
    Array arr1 = new Array(5);
    SortArray arr2 = new SortArray(5);
    ReverseArray arr3 = new ReverseArray(5);
    System.out.println(arr2.add(11));
    System.out.println(arr2.add(2));
    System.out.println(arr2.add(32));
    System.out.println(arr2.add(24));
    System.out.println(arr2.add(15));
    arr2.increment(3);
    System.out.println(arr2.add(26));
    System.out.println(arr2.add(1));
    System.out.println(arr2.add(7));
    int [] result = arr2.getData();
    for(int x = 0; x < result.length; x++) {
      System.out.print(result[x] + "、");
    }
  }
}