Practice problem on defining and using Class types. Part 4.

Transcription

1 CS180 Programming Fundamentals Practice problem on defining and using Class types. Part 4. Implementing object associations: Applications typically consist of collections of objects of different related classes, working together. Given class Employee and BankAccount, implement direct deposit as a form of payment to their employees. (The account owner may not be the same person as the employee) CLASS Employee String name double payrate double unpaidhours getname() getpayrate() giveraise(double percent) setpayrate(double newrate) getunpaidhours() incrementhoursby(int hrs) DirectDeposit to CLASS BankAccount String owner String id double balance static int numaccounts getid() getbalance() deposit(double amt ) withdrawal(double amt ) We already have the separate class definitions for class Employee and BankAccount To implement direct deposit feature, perform the following using the Employee and Bank Account class specifications: a) Add a field of type BankAccount to each Employee object. b) Add a new constructor to allow for specification of direct deposit account as well as the name and pay rate of an employee. c) Add accessor and mutator methods for the direct deposit instance variable. d) Add instance method pay to Employee class, which should work as follows: Calculate the amount due to employee for unpaidhours. In case employee does not have the direct deposit account specified on record (i.e. the value of the appropriate instance var is null), print a check for the specified amount. Otherwise, if direct deposit account field is not null, deposit the amount due to the employee on their direct deposit account (Hint: use instance method deposit of the BankAccount class). Reset the number of unpaidhours to 0. e) *** update Employee class to keep track the percentage of all Employee objects that have direct deposit accounts. f) *** update Employee class so that no employee rate is below the minimum pay rate.

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3 /** Class that represents an employee with name, hourly pay rate, unpaid hours */ public class Employee { // instance variables private String name; private double payrate; private int unpaidhours; private static DecimalFormat MONEY = new DecimalFormat("#,##0.00"); // Constructor public Employee (String name, double hourlyrate){ this.setname(name); this.payrate = hourlyrate; public void setunpaidhours(int unpaidhours) { this.unpaidhours = unpaidhours; public String tostring() { String result = this.getname() + " is paid " + MONEY.format(this.getRate()) + " per hour. " + " Unpaid hours: " + this.getunpaidhours(); return result; public String getname (){ return this.name; public double getrate (){ return this.payrate; public int getunpaidhours() {return this.unpaidhours; // mutators /** setname - method that sets value of instance var name * to a String that is passed in as a parameter */ public void setname (String name){ this.name = name; /** Mutator that increments the number of hours worked * Returns the updated value of unpaidhours */ public int incrementhoursby( int addidionalhours){ this.unpaidhours += addidionalhours; return this.unpaidhours; /** Mutator that assigns the pay rate to rate * passed as parameter */ public void setpayrate ( double rate){ if (rate < 0){ System.out.println("Pay rate cannot be below $" + 0); else this.payrate = rate;

4 /** public void giveraise (double percent){ * increases the pay rate by specified percent value */ public void giveraise (double percent){ double newrate = 0; // this is a local variable newrate = this.payrate *(percent +1); // set the calling object's rate to newrate this.payrate = newrate;

5 /** Class developed for the in-class practice from Handout 9 */ public class BankAccount { private String owner; private double balance; private String id; private static int countaccounts = 0; // how many accounts were created so far public static final DecimalFormat ACC_FORMAT = new DecimalFormat("00000"); public BankAccount (String accountholder){ this(accountholder, 0); // call the 2-arg constructor // to set the balance to 0 // this() refers to a constructor // Constructor which creates an account with the specified (b) initial deposit public BankAccount (String accountholder, double b){ this.owner = accountholder; this.balance = b; countaccounts++; this.id = ACC_FORMAT.format( countaccounts); // method tostring() public String tostring(){ return "id = " + this.id + " owner "+ this.owner + " has $" +this.balance; public String getowner() { return this.owner; public double getbalance() {return this.balance; /** Method deposit(double adeposit) * adds adeposit to the calling object's balance as long as adeposit is nonnegative. Otherwise leaves balance unchanged. Returns the updated balance.*/ public double deposit (double adeposit){ if (adeposit >=0) this.balance = this.balance + adeposit; return this.balance; /** Method withdrawal(double amt) * If amt is positive and if the calling object's balance is sufficient * to cover the amt, reduce the balance of calling * object by amt. Return true. Otherwise, return false. */ public boolean withdrawal (double amt) { boolean check= true; // will store return value if (amt < this.balance && amt > 0) this.balance = this.balance - amt; else check = false; return check;