Thread: How do I do this, code supplied

Hey I am doing a tutorial at uni and I need to write a code that

Task 3
Write a program that accept from the command line number n and then print stars ‘*’ in n rows.
For example, if n = 5 then the program should print:
*
* *
* * *
* * * *
* * * * *
Note that you must let the user input the number for rows from the command line. For example, if the command line input is 5, you will have args[0] = "5". Then you can use
int n = Integer.parseInt(args[0]); // now n=5

here is my code so far, I have asked my tutorial teacher. All she did was pass me a pen and paper and smile and there is nothing in the lectures about how to do it. Any help, as quick as possible would be appreciated.

public class ArgsLoop {
public static void main(String[] args) {
int n = Integer.parseInt(args[0]); // now n=5
for(int i=0;r<n;i++){
System.out.println("*");
for(int c=i; c<n; c++){
System.out.print("*");
}
}
}
}

for(int i = 0; r < n; i++) {
Where does the 'r' come from?

Please use code tags when posting code, help can be found here

public class ArgsLoop {
	public static void main(String[] args) {
	int n = Integer.parseInt(args[0]); // now n=5
		for(int i=1;i<n;i++){
			System.out.println("*");
			for(int c=0; c<i; c++){
				System.out.print("*");
			}
			}
		}
	}

i is suppose to be the rows, c is the columns I've been working on it a bit, it comes up with the result

*
**
***
****
****
now

That's not helping ^. Can you show me how to do it in code, don't you think I have used paper and pen? That's exactly what I wrote in my first post.
I have been playing around with this code for hours, I know it's something simple. But that is really not helping it at all. I already have the second loop to set up to not write lines.

for(int i=0;i<n;i++){
System.out.println("*");

I fixed the outer loop,
it runs five times now, but the inner loop still isn't working

public class ArgsLoop {
	public static void main(String[] args) {
	int n = Integer.parseInt(args[0]); // now n=5
		for(int i=0;i<n;i++){
			System.out.println("*");
			for(int c=i; c>-1; c--){
				System.out.print("*");
			}
		}
	}
}

Originally Posted by MooseManX

but the inner loop still isn't working

...and describe what isn't working means.

it is posting an extra line e.g

*
**
***
****
*****
*****
that's my output now

public class ArgsLoop {
	public static void main(String[] args) {
	int n = Integer.parseInt(args[0]); // now n=5
		for(int i=0;i<n;i++){
			System.out.println();
			System.out.print("*");
			for(int c=i-1; c>-1; c--){
				System.out.print("*");
			}
		}
	}
}

Okay that just clicked what you meant, played around with my code some more
and I have come up with this output which is correct except a space is placed here. I'm not sure if this will matter or not could you explain why it is there

< there is a space here
*
**
***
****
*****

Originally Posted by MooseManX

could you explain why it is there

< there is a space here
*
**
***
****
*****

System.out.println();
is the first thing inside the loop, so it is the first thing that happens
Put the System.out.println(); somewhere else.
If you worked this out on paper, step by step, it would have been clear how to make it work before you wrote public class ArgsLoop

public class ArgsLoop {
	public static void main(String[] args) {
	int n = Integer.parseInt(args[0]); // now n=5
		for(int i=0;i<n;i++){
			System.out.print("*");
			System.out.println();
			for(int c=i; c>-1; c--){
				System.out.print("*");
			}
		}
	}
}

If I separate them like this my output just becomes.

*
**
***
****
*****
*****
again

Back to the drawing board. (or pencil and paper)
Hint, you do not need two lines that say System.out.print("*");
Come up with how to do it first, then translate that solution to code

public class ArgsLoop {
	public static void main(String[] args) {
	int n = Integer.parseInt(args[0]); // now n=5
		for(int i=0;i<n;i++){
			System.out.println();
			for(int c=i; c>-1; c--){
				System.out.print("*");
			}
		}
	}
}

So I realized I do not need the outer * print. However this is still leaving me with a new line before the result

When you did it on paper, (because we know you did this first, because it makes writing the code easier), did you move to a new line and then write *; or did you write * and then move to a new line?
What does the code do? Write * or go to a new line first?