How to print this in java?

[yaseen]

How to print this in java?


1
2 1
1 2 3
4 3 2 1
1 2 3 4 5
6 5 4 3 2 1

[Sno]

1. This seems like entry level homework (since I did this)
2. Wrong section.
3. Research Loops
4. This example should be in google
5. System.out.println

[Fubarable]

1. This seems like entry level homework (since I did this)
2. Wrong section.

Yep. Moving to New to Java section.

[Norm]

One answer is to Use the println() statement. Code the data for the each line followed by the newline characters until you've got all the lines

Or is your question, how to generate the data?

Look at the data, line by line.
Two things can be seen:
The data gets longer for each line
The order of the data reverses line by line

Make a method that takes the line number and returns the data as needed for that line.

[Eranga]

How to print this in java?


1
2 1
1 2 3
4 3 2 1
1 2 3 4 5
6 5 4 3 2 1

Do you know how this pattern generated? And what you've tried so far?

[bayan]

boolean reverse = false;
for(int i=0; i<6;i++)
{
     if(reverse)
     {
           for(int j=1, j<i; j++)
           {
                 System.out.print(j);
                 reverse=!reverse;
           }
      }
      else
      {
              for(int j=i;  j>0; j--)
              {
                      System.out.print(j);
                       reverse=!reverse;
              }
      }
      System.out.println();//j was a typo sorry
}

Just post if you need an explanation

[Tolls]

You could always explain...why?

[JosAH]

You could always explain...why?

Don't be an unthankful rapscallion; be grateful for the spoonfed magical solution instead; copy and paste the beautiful gem and use it in utmost delight. Don't question the algorithm and don't ask for a why, it just came to us in merci, halleluya.

kind regards,

Jos ;-)

[j2me64]

Just post if you need an explanation

the used j in the last println is out of scope, since j was declared inside the else block. but it's a quick fix to correct and thx for the code.

[JosAH]

the used j in the last println is out of scope, since j was declared inside the else block. but it's a quick fix to correct and thx for the code.

The loop boundaries are also shaky at best. Try to start with 'reverse= true' if you want the other pyramid; it doesn't work. It is crappy code.

kind regards,

Jos

[sduskis]

In groovy, it would look like this:

(1..6).each{

((it%2) ? (it..1) : (1..it)).each{print "$it ";}
println ""

}

[JosAH]

In groovy, it would look like this:

Why does it say "Java Forums" on top of each page?

kind regards,

Jos

[Tolls]

The loop boundaries are also shaky at best. Try to start with 'reverse= true' if you want the other pyramid; it doesn't work. It is crappy code.

kind regards,

Jos

But its free!

...or, yet another reason I hate code dumps. First, as you implied above, they don't help learning, and second they're often not all that good.

And as for the Groovy example, that really...really...really isn't selling me on that language.

[sduskis]

Points about Groovy Taken. However, there are 2 things to notice from the Groovy approach that ported, in various degrees of complexity to Java.

1) reverse = !reverse can be accomplished with alternative means. if(i % 2 == 1) <do reverse> else <do forward>. That looks a bit ugly, but processing of "rows" based on the remainder function is a pretty common solution to this type of problem.

2) Closures have been discussed in regards to Java for quite a while. The "how you iterate" vs. "what you do in the loop" is. In the java world, those two concepts are tightly coupled.

Taking #1 into account, here's what the algorithm looks like:

for(int i=1; i<=6;i++)
{

if(i%2==1)
{

for(int j=1; j<=i; j++)

System.out.print(String.valueOf(j)+" " );

}
else
{

for(int j=i; j>0; j--)

System.out.print(String.valueOf(j)+" " );

}
System.out.println();

}

It's important to note that #2 shouldn't be addressed in a Java world on a simple case like this one, but should be thought about for more complex scenarios.

[wzq110120]

I can frome china,I want to make friend with you,My MSN is esxwazq123@hotmail.com
My replay:

int target = 6;
for(int i = 1;i<=target;i++){

if(i%2!=0){
for(int j = 1; j<=i; j++)
System.out.print(j);
}else{
for(int k= i; k>0; k--)
System.out.print(k);
}
System.out.println();
}

[svidurs1]

A little more interactive. You can enter (at runtime) the number of lines for which you want to repeat this pattern.

import java.io.*;
public class Pattern{
	public static void main (String[] args) throws IOException{
		System.out.print("Enter the number of lines for which you want this pattern.: \t");
		int noOfLines = Integer.parseInt((new BufferedReader(new InputStreamReader(System.in))).readLine());
		for(int i=1; i<=noOfLines;i++)
		{
		     if((i%2) == 0)
		     {
		           for(int j=i; j>=1; j--)
		           {
		                 System.out.print(j + "  ");
		           }
		      }
		      else
		      {
		              for(int j=1;  j<=i; j++)
		              {
		                      System.out.print(j + "  ");
		              }
		      }
		      System.out.println();
		}
	}
}

[Eranga]

Please use code tags when you are posting here in the forum. Unformated codes are really hard to read. If you don't know how to do it, check on my forum signature.

[svidurs1]

Point taken. !!

import java.io.*;
public class Pattern{
	public static void main (String[] args) throws IOException{
		System.out.print("Enter the number of lines for which you want this pattern.: \t");
		int noOfLines = Integer.parseInt((new BufferedReader(new InputStreamReader(System.in))).readLine());
		for(int i=1; i<=noOfLines;i++)
		{
		     if((i%2) == 0)
		     {
		           for(int j=i; j>=1; j--)
		           {
		                 System.out.print(j + "  ");
		           }
		      }
		      else
		      {
		              for(int j=1;  j<=i; j++)
		              {
		                      System.out.print(j + "  ");
		              }
		      }
		      System.out.println();
		}
	}
}

[Eranga]

No need of doing that actually. I've already do that, keep in mind to do it next time onwards. :)

[svidurs1]

yeah i know.. was just figuring out if its done this way !!
sry for playin around !!