1、设计一个包含多个构造方法的类，并分别用这些构造方法实例化对象
class Figure { public String name; public int age; public String gender; Figure(){} Figure(String name,int age){ this.name = name; this.age = age; } Figure(String name,int age ,String gender){ this.name = name; this.age = age; this.gender = gender; } } public class Text01 { public static void main(String[] args){ Figure one = new Figure("孙悟空",500,"男");//创建对象one System.out.println("第一个人物是:"); System.out.println(one.name);//使用对象 System.out.println(one.age); System.out.println(one.gender); Figure two = new Figure("唐僧",30);//创建对象two System.out.println("第二个人物是:"); System.out.println(two.name);//使用对象 System.out.println(two.age); } }
2、编写一个类Calculate1，实现加、减两种运算，然后，编写另一个派生类Calculate2，实现乘、除两种运算
Calculate1：
public class Calculate1 { //加法运算 public double sum(double sum1,double sum2){ return sum1+sum2; } //减法运算 public double substruction(double sub1,double sub2){ return sub1-sub2; } }
派生类Calculate2：
public class Calculate2 extends Calculate1{ //因为继承了Calculate1故加法和减法可以用父类的 //乘法运算 public double multiply(double mul1,double mul2){ return mul1*mul2; } //除法运算 public double divide(double div1,double div2){ return div1/div2; } }
3、建立三个类：居民、成人、官员。居民包含身份证号、姓名、出生日期，而成人继承自居民，多包含学历、职业两项数据；官员则继承自成人，多包含党派、职务两项数据。要求每个类的字段都以属性的方式对外提供数据输入输出的功能
居民类：
import java.util.Date; public class Resident { private String idCard; private String name; private Date birth; public String getIdCard() { return idCard; } public void setIdCard(String idCard) { this.idCard = idCard; } public String getName() { return name; } public void setName(String name) { this.name = name; } public Date getBirth() { return birth; } public void setBirth(Date birth) { this.birth = birth; } }
成人继承自居民：
public class Adult extends Resident { private String education; private String vocation; public String getEducation() { return education; } public void setEducation(String education) { this.education = education; } public String getVocation() { return vocation; } public void setVocation(String vocation) { this.vocation = vocation; } }
官员则继承自成人：
public class Official extends Adult { private String party; private String duties; public String getParty() { return party; } public void setParty(String party) { this.party = party; } public String getDuties() { return duties; } public void setDuties(String duties) { this.duties = duties; } }
4、编写一个类，其中包含一个排序的方法sort(),当传入的是一串整数，就按照从小到大的顺序输出，如果传入的是一个字符串，就将字符串反序输出
import java.util.Arrays; public class Comment { public static void main(String[] args) { String[] objs = { "f", "b", "m", "c", "y" }; int[] obj = { 1, 2, 5, 3, 8 }; objs = sort(objs);//调用方法排序 obj = sort(obj); //输出已经排序好的字符串 for (String i : objs) { System.out.print(i + " "); } System.out.println(); for(int s : obj) { System.out.print(s + " "); } } public static int[] sort(int[] nums) { Arrays.sort(nums); return nums; } // 冒泡排序 public static String[] sort(String[] strs) { for (int i = 0; i < strs.length; i++) { for (int j = 0; j < strs.length - i - 1; j++) { if (strs[j].compareTo(strs[j + 1]) < 1) { String temp = strs[j]; strs[j] = strs[j + 1]; strs[j + 1] = temp; } } } return strs; } }
5.设计一个立方体类Box，它能计算并输出立方体的体积和表面积
import java.util.Scanner; public class Box { double length; double width; double height; // 求立方体体积 double volume(double length, double width, double height) { return length * width * height; } // 求立方体表面积 double area(double length, double width, double height) { return 2 * (length * width + length * height + width * height); } public static void main(String[] args) { Box box = new Box(); // 实例化一个对象 System.out.println("请输入该立方体的长、宽、高："); Scanner sc = new Scanner(System.in); box.length = sc.nextDouble(); box.width = sc.nextDouble(); box.height = sc.nextDouble(); System.out.println("立方体的体积为：" + box.volume(box.length, box.width, box.height)); // 调用方法 System.out.println("立方体的表面积为：" + box.area(box.length, box.width, box.height)); } }
6.编写一个程序，设计一个点类Point，实例化两个点之后，能调用其方法求两个点之间的距离
点类Point：
public class Point { private double x ; private double y ; public Point(double x, double y) { this.x = x; this.y = y; } public static void distance(Point p1,Point p2) { double sum = Math.sqrt(Math.pow(p1.x-p2.x, 2)+Math.pow(p1.y-p2.y, 2)); System.out.println(sum); } }
点类Point的测试类：
public class PointDemo { public static void main(String[] args) { Point.distance(new Point(0,0), new Point(3,4)); } }
7、 写一个学生类，包括属性： 学号，班号，姓名，年龄，性别；要求用无参构造，方法获得：学号，班号，姓名，年龄（只能小于100岁，大于1，否则重新输入） ，性别（只能男或者女，否则重新输入），最后在主方法输出你对一个学生对象赋值的信息
public class Student { static int studentID; static int classID; static String name; static int age; static char sex; public Student() { } public int getStudentID() { return studentID; } public void setStudentID(int studentId) { this.studentID = studentId; } public int getClassID() { return classID; } public void setClassID(int classID) { this.classID = classID; } public String getName() { return name; } public void setName(String name) { this.name = name; } public int getAge() { return age; } public void setAge(int age) { if (age > 1 && age < 100) this.age = age; else throw new RuntimeException("输入年龄：大于1，小于100"); } public char getSex() { return sex; } public void setSex(char sex) { if (sex == '男' || sex == '女') this.sex = sex; else throw new RuntimeException("只能男或者女"); } public static void main(String[] args) { Student aa = new Student(); aa.setStudentID(54321); aa.setClassID(121); aa.setName("风清扬"); aa.setAge(20); aa.setSex('男'); System.out.println("学号：" + studentID + "\n" + "班号：" + classID); System.out.print("姓名：" + name + "\n" + "年龄：" + age + "\n" + "性别：" + sex); }
8、设计一个BankAccount类，实现银行某账号的资金往来账目管理，包括建账号、存入、取出等。BankAccount类包括，账号（BankAccountId）、开户日期Date(日期)，Money(金额)，Rest(余额)。另有一个构造方法和三个成员方法Bankin()(处理存入账)，Bankout()处理取出账)和和一个负责生成账号的自动增长的方法
class BankAccount { String Date; double Money; String BankAccountId; public BankAccount() { BankAccountId = ""; Money = 0.0; } public BankAccount(String ID, String date, double balance) { Date = date; BankAccountId = ID; Money = balance; } public String getBankAccountId() { return BankAccountId; } public void getBankAccountId(String ID) { BankAccountId = ID; } public double getBalance() { return Money; } public void printAccountMsg() { System.out.print("账户名：" + BankAccountId + " 开户日期 " + Date + " 当前余额" + Money + "元\n"); } public void Bankin(double money) { System.out.print("此次存入：" + money + "元 "); Money += money; } public void Bankout(double money) { System.out.print("此次取出：" + money + "元 "); if (money <= Money) Money -= money; else System.out.print("账户余额不足，操作失败！"); } } public class Test { public static void main(String[] args) { BankAccount user = new BankAccount("user", "2020-03-24", 150000); user.printAccountMsg(); user.Bankin(15000); System.out.println(); user.printAccountMsg(); user.Bankout(288888); System.out.println(); user.printAccountMsg(); } }
9、编写一个程序，已有若干学生数据，包括学号、姓名、成绩，要求输出这些学生数据并计算平均分。思路：设计一个学生类Stud,除了包括no(学号)、name(姓名)、和deg(成绩)数据成员外。有两个静态变量sum和num，分别存放总分和人数，另有一个构造方法、一个普通成员方法disp()和一个静态成员方法avg()，它用于计算平均分
public class Stud { int no; String name; double deg; static double sum = 0; static int num = 0; public Stud(int no, String name, double deg) { this.no = no; this.name = name; this.deg = deg; disp(); sum += deg; num++; } public void disp() { System.out.println("学号：" + this.no + "\t姓名：" + this.name + "\t成绩：" + this.deg); } public static void avg() { System.out.println("平均分:" + sum / num); } public static void main(String[] args) { Stud[] studs = new Stud[5]; studs[0] = new Stud(2022001, "张三", 88); studs[1] = new Stud(2022002, "李四", 77); studs[2] = new Stud(2022003, "王五", 68); studs[3] = new Stud(2022004, "杨六", 87); studs[4] = new Stud(2022005, "刘七", 95); Stud.avg(); } }
10.编写一个程序，统计学生成绩，其功能包括输入学生的姓名和成绩，按成绩从高到低排列打印输出，对前70%的学生定为合格(PASS)，而后30%的学生定为不合格(FAIL)。思路： 设计一个类student,包含学生的姓名和成绩等数据。设计一个类Compute: sort()、disp()，它们分别用于按成绩排序和输出数据
Compute类：
public class Compute { public void sort(Student [] students){ for(int i = 0;i < students.length;i++){ for(int j = i;j < students.length;j++){ if(students[i].deg < students[j].deg){ Student temp = students[i]; students[i] = students[j]; students[j] = temp; } } } } public void disp(Student[] students){ sort(students); for(int i = 0;i < students.length;i++){ if(i <= students.length*0.7-1){ System.out.println("姓名："+students[i].name+" 成绩："+students[i].deg+" PASS"); }else { System.out.println("姓名："+students[i].name+" 成绩："+students[i].deg+" FAIL"); } } } }
Student类：
public class Student { String name; double deg; public Student(String name, double deg) { this.name = name; this.deg = deg; } }
Demo类：
public class Demo { public static void main(String[] args) { Student[] s = new Student[5]; s[0] = new Student("张三",79); s[1] = new Student("李四",88); s[2] = new Student("王五",56); s[3] = new Student("杨六",75); s[4] = new Student("刘七",65); Compute compute = new Compute(); compute.disp(s); } }
