Thread: Help understanding Objects and Constructers

Hello Java friends,

I'm struggling to understand objects and classes.

Can someone please tell me why in the first code snippet for the Rectangle class the object is declared on two separate lines?

Rectangle myRectangle;

System.out.print ("Please enter length of rectangle: ");
rectangleLength = keyboard.nextDouble();

System.out.print ("Please enter height of rectangle: ");
rectangleHeight = keyboard.nextDouble();

//create new Rectangle object (myRectangle)
myRectangle = new Rectangle(rectangleLength, rectangleHeight);

i.e Why does the example create a reference to the object Rectangle, then you take in the parameters and then create the object at the end????


Yet in the second example of the BankAccount class the object is declared on one line? What is the difference?

BankAccount account1= new BankAccount ("12345,", "Ben Murphy");

System.out.print("Enter amount the deposit");
amount = keyboard.nextDouble();
//object.method.parameter
account1.deposit(amount);

System.out.print("Deposit was made");
System.out.println("Balance = " + account1.getBalance());

System.out.println();

System.out.println("Enter amount to withdraw: ");
amount = keyboard.nextDouble();
ok = account1.withdraw(amount);


Are these two ways of doing the exact same thing? Are they both constructors?

I have watched videos, done example tutorials yet I seem to be struggling with this concept. Many thanks.

Because the scanner must read in height and length, before they are passed as parameters. The BankAccount Class, on the other hand doesn't require parameters to be read in. There both objects, the constructor would normally be in tester.

Ahhhhhhh! Damn I can't believe I overlooked that! I have spent days on this before posting in here.

Thank you llowe29! Much respect to you!

--- Update ---

Hey Junky,

Ah I see. Now I understand my own confusion too. Thank you! How long have you been programming Java? I find it easier to modify code, than write code from scratch.

Can you offer any tips? I want to get a trainee Java job and I am kinda struggling with some concepts. How long did it take you to learn? What's the secret?

Originally Posted by thedarkhitman

How long have you been programming Java?How long did it take you to learn?

More years than the average person has been alive. Considering the accelerated growth of computer science starting years ago and continuing on, we are all still learning every day. It is a journey, not a destination

Originally Posted by thedarkhitman

I find it easier to modify code, than write code from scratch.
Can you offer any tips?

Start writing code from scratch. It is the best way to develop the ability to write code from scratch.

Originally Posted by thedarkhitman

I want to get a trainee Java job and I am kinda struggling with some concepts. What's the secret?

Write code. Write something you can handle. Modify it. Rewrite it. Ask for ideas from friends. Do other people's assignments that are posted on the forum (just don't give them the solution!).