10) If you write a class called Car, but do not write a toString( ) method. Then
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10) If you write a class called Car, but do not write a toString( ) method. Then in main( ) you create a Car object like this:
//assume a constructor exists that takes these parameter types
Car myCar = newCar(“Toyota”, “Corolla”, 1994, “blue”);
System.out.println(“This is myCar information: “ + myCar.toString( ) );
Explain what will happen and why that will happen.
11) Suppose you have a class called BankAccount that is abstract. Then you have a concrete class called SavingsAccount that extends BankAccount.
BankAccount has an abstract method called withdrawFunds(double amountToWithdraw) and a non-abstract method called depositFunds(double amountToDeposit ).
SavingAccount does NOT have its own version written for depositFunds(double);
There are four questions here.
a)Is this a valid declaration?
BankAccount myAccount = new SavingsAccount( );
answer:
b)Is this a valid declaration?
SavingsAccount myAccount = new BankAccount( );
answer:
Suppose you have this code:
c)
SavingsAccount myAccount = new SavingsAccount( );
myAccount.depositFunds(200);
What code (from which class) will execute as a result of that method call?
answer:
__________________________________________________________________
d)
myAccount.withdrawFunds(100);
What code (from which class) will execute as a result of that method call?
answer:
Explanation / Answer
(10)
All classes in java implements Object class .
So toString() Function can be called on any type of object in java.
It is a valid statement.
toString() function returns textual representation of any object.
it will return string which represents the given object in text format.
(11)
a)Is this a valid declaration?
BankAccount myAccount = new SavingsAccount( );
Yes this is a valid declaration. As all saving accounts are bank accounts.
b)Is this a valid declaration?
SavingsAccount myAccount = new BankAccount( );
This is not a valid declaration as BankAccount is super class and also abstract class. we can not have object of type BankAccount.
Suppose you have this code:
c)
SavingsAccount myAccount = new SavingsAccount( );
myAccount.depositFunds(200);
What code (from which class) will execute as a result of that method call?
SavingsAccount doesnt have its own implementation for function depositFunds(). So depositFunds() of parent class, i.e BankAccount class will be implemented.
d)
myAccount.withdrawFunds(100);
What code (from which class) will execute as a result of that method call?
This statement will implement the fucntion withdrawFunds() that is defined inside class SavingAccount.
as it is abstract fucntion , its implementationmust be there in SavingAccount class.
if you have any doubts, you can ask in comment section.
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