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write a method called printTriangle. How to start?

Posted on 2008-10-20
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Last Modified: 2013-11-23
(Objects first with java, A practical Introduction using Blue J, Third Ed, David J. Barnes & Michael Kolling)

Hi

I have to write a method called printTriangle.

example:  printTriangle(4);

output should look like this:

*
**
***
****

and I don't know how to start. Can you please give me an advice?
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Question by:bt1942
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9 Comments
 
LVL 20

Expert Comment

by:chaitu chaitu
ID: 22764318
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Author Comment

by:bt1942
ID: 22764354
chaituu// that seems very complicated, I just need to write a simple method soething like

               
public void printTriangle()
	{
	    int n = 4;
	    String s = "*";
	    for(int row = 1; row<= n; row++)
	    {
	        System.out.println(s);
	      
	       }
	   }
}

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LVL 6

Accepted Solution

by:
javaexperto earned 200 total points
ID: 22764396
the first thing you need is one loop to print "*" and other loop to print a new line. Your first loop will get up to your parameter and the second will enter the first time one,  the second two, etc. The loops must be nested, here the method:
public void printTriangle(int stars) {
    for(int i = 0; i < stars; i++) {
        for(int j = 0; j <= i; j++)  {
	    System.out.print("*");	
	}
	    System.out.println("");
    }
}

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LVL 3

Assisted Solution

by:siranm
siranm earned 100 total points
ID: 22764405
here you go....

public void printTriangle()
        {
            int n = 4;
            String s = "*";
            for(int row = 1; row<= n; row++)
            {
 
for(int stars=1; stars<=row;start++){
                System.out.println(s); //1st row->1star, 2nd row->2stars,...                    
}
           }
}

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Expert Comment

by:siranm
ID: 22764410
yep, javaexperto, i missed that detail on the new line ; )
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LVL 3

Assisted Solution

by:glenjr
glenjr earned 100 total points
ID: 22764419
bt1942,

you are on the right track. right now your program prints out:

*
*
*
*

In order to adjust it so that it prints out the way you want you need to the following line below your system.out...:

s+= "*";


Also, make sure your {} match and that you have a main method in there some where.

Let me know if you have questions.

glenjr
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LVL 3

Expert Comment

by:glenjr
ID: 22764424
looks like i wasnt the only one working on it, i wasnt fast enough :)
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Assisted Solution

by:chaitu chaitu
chaitu chaitu earned 100 total points
ID: 22764430
public static void main(String[] args) {

             int n = 4;
           String s = "*";
           String s1 = "";
       for(int row = 1; row<= n; row++)
       {

for(int stars=1; stars<=row;stars++){
      s1+=s;
           System.out.println(s1); .                    
}
      }
       }
0
 

Author Closing Comment

by:bt1942
ID: 31508140
Thanks for your help!
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