CPSC 220 Chapter 3 Answers

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Sample questions from Chapter 3 and student-provided answers--waiting on instructor to proof-read and correct if necessary.

Give an example of each:

1. A Method definition containws an access specifier (usually public), a return type, a method name, parameters and the method body.

• public void deposit(double amount)

2. Constructors contain instructions to initialize objects. The constructor name is always the same as the class name.

• CashRegister = new CashRegister();

3. An object uses instance fields to store its state--the data that it needs to execute its methods.

• private double bounds;

4. Each object of a class has its own set of instance fields.

• YourSavings {...} MomsSavings has its own balance.

5. You should declare all instance fields as private.

• Private double payment;

6. Constructors contain instructions to initialize the instance fields of an object.

• public BankAccount
  • Balance = 0;

7. Use the return statement to specify the value that a method returns to its caller.

8. Instance fields are initialized to a default value, but you must initialize local variables belonging to a method--they die when the method exits.

• Ur Savings --> Balance
  • getInterest(doubleDeposit);

9. Instance fields are initialized to a default value, but you must initialize local variables.

• double new Balance = balance + amount;

10. The implicit parameter of a method is the object on which the method is invoked. The this reference denotes the implicit parameter.

• this.Balance = newBalance;

11. Use of an instance field name in a method denotes the instance field of the implicit parameter.

• public void deposit(double amount)

{

• • double newBalance = this.balance amount;
  • this.balance = newBalance;

}