java小作业，求大神帮忙。。。

interface Salary{
public float charge();
}
class PersonTest{
private String name;
private int age;
private float salary;
PersonTest(){
}
PersonTest(String name, int age) {
this.name = name;
this.age = age;
}
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 float getSalary() {
return salary;
}
public void setSalary(float salary) {
this.salary = salary;
}
}
class CalculateTime extends PersonTest implements Salary{
private int worktime;
private float pricetime;
CalculateTime() {
super();
}
public CalculateTime(String name, int age,int worktime,float pricetime) {
super(name, age);
this.worktime = worktime;
this.pricetime = pricetime;
super.setSalary(charge());
}
@Override
public float charge() {
return worktime*pricetime;
}
}
class CalculateNum extends PersonTest implements Salary{
private int worknum;
private float workprice;
public CalculateNum() {
super();
}
@Override
public float charge() {
return this.worknum*this.workprice;
}
public CalculateNum(String name, int age,int worknum,float workprice) {
super(name, age);
this.worknum = worknum;
this.workprice = workprice;
setSalary(charge());
}
public int getWorknum() {
return worknum;
}
public void setWorknum(int worknum) {
this.worknum = worknum;
}
public float getWorkprice() {
return workprice;
}
public void setWorkprice(float workprice) {
this.workprice = workprice;
}
}
class CalculateBargain extends PersonTest implements Salary{
private int base;
private int worknum;
private float workprice;
public CalculateBargain(String name, int age,int base,int worknum,float workprice) {
super(name, age);
this.base = base;
this.worknum = worknum;
this.workprice = workprice;
super.setSalary(charge());
}
@Override
public float charge() {
return base + worknum*workprice;
}
public int getBase() {
return base;
}
public void setBase(int base) {
this.base = base;
}
public int getWorknum() {
return worknum;
}
public void setWorknum(int worknum) {
this.worknum = worknum;
}
public float getWorkprice() {
return workprice;
}
public void setWorkprice(float workprice) {
this.workprice = workprice;
}
}
public class Test {
public static void main(String[] args) {
CalculateTime Ctime = new CalculateTime("Tom",22,40,8);
CalculateNum Cnum = new CalculateNum("Mike",19,800,3);
CalculateBargain Cbar = new CalculateBargain("Lee",33,1000,800,2);
System.out.println("计时工："+Ctime.getName()+"的工资是 "+Ctime.getSalary());
System.out.println("计件工："+Cnum.getName()+"的工资是 "+Cnum.getSalary());
System.out.println("合同工："+Cbar.getName()+"的工资是 "+Cbar.getSalary());
}
}