Thread: Do-while loop help

Originally Posted by Norm

Can you explain? Are you asking how to only call println() one time and have it print all the results?
If that is want you mean, you could use String concatenation to build a String will all the results and then call println() one time to print that String.

int g = b.nextInt(), sum = 0, r = 0, f = g;

Putting multiple statements one on line tends to hide what the code is doing.
It would be better to split that line into several lines.

What I'm trying to do is to make only one System.out.println that will print every iteration. For example, if I enter in "6" into the command prompt, I would like this to be printed.

36
25
16
9
4
1

Originally Posted by Norm

What is f for? Would using just g work?

Yes I believe it would, but I don't know how to use g twice in the loop. :/

Using the method I'm using, I would have a lot of code, so I realized I couldn't keep doing it the way I am.

Originally Posted by Norm

what if only f were used and the f-- statement was moved?

I honestly don't know how I would set that up. sorry

Just think about the problem a bit more.
You are wanting to start at a given number, square it and print it out, then subtract one from it.

So just some example of pseudocode:

Create variable for storing the input number
Create variable for storing sum

Loop while input number is greater than 0
Assign sum to be the input squared
Print out sum
Decrement the input number
Continue loop

Hopefully this helps a little bit without giving too much away

Originally Posted by Parranoia

Just think about the problem a bit more.
You are wanting to start at a given number, square it and print it out, then subtract one from it.

So just some example of pseudocode:

Create variable for storing the input number
Create variable for storing sum

Loop while input number is greater than 0
Assign sum to be the input squared
Print out sum
Decrement the input number
Continue loop

Hopefully this helps a little bit without giving too much away

This does help a lot, but do I create these variables in or out of the loop? Or does it not matter?

--- Update ---

Ok, so I think I improved my code. Thanks @Parranoia.

System.out.print("\nPlease enter an integer. ");						
		Scanner b=new Scanner(System.in);	
		int g = b.nextInt(), sum = 0;											
 
		do
		{
			sum = g * g;
		System.out.println("\n" + sum);
			g--;	
		}
		while(g<0);

The only thing is, is that I don't know how to continue my loop. If I entered in "5" right now with this code, it only prints out 25.

Variables created inside a loop will only exist while that loop is running. Take this as an example:

int num = 0;
 
for (int i = 0; i < 5; i++)
{
    num = i * i;
    int sum = 2;
}
 
System.out.println(num);
System.out.println(sum); // This will not compile as it is not defined in this scope

If you need a variable to persist after a loop has completed, you must define it outside of the loop.
At the end of each loop the variable sum would get destroyed then created again at the start of the next loop.

In this example, you can access the variable num even after the loop has completed, but not sum.

--- Update ---

Originally Posted by phlegm

This does help a lot, but do I create these variables in or out of the loop? Or does it not matter?

--- Update ---

Ok, so I think I improved my code. Thanks @Parranoia.

System.out.print("\nPlease enter an integer. ");						
		Scanner b=new Scanner(System.in);	
		int g = b.nextInt(), sum = 0;											
 
		do
		{
			sum = g * g;
		System.out.println("\n" + sum);
			g--;	
		}
		while(g<0);

The only thing is, is that I don't know how to continue my loop. If I entered in "5" right now with this code, it only prints out 25.

The logic of your do-while loop is: do such and such while g is less than 0

I figured it out, thanks everyone (Parranoia, and Norm).

It was a very foolish error. The control statement was (g<0), when it should of been (g>0). I feel dumb. But thanks!

Everybody has been there buddy it'll only get better and better with time. Glad to help out.