Converting Multidimensional array into 1D array

[Seth Lamb]

import java.util.*;
import java.text.*;


public class Linearize {

	public static void main(String[] args) {

		// Create new Scanner and Random and Decimal objects
		Scanner s = new Scanner (System.in);
		Random g = new Random ();
		DecimalFormat oneplaces = new DecimalFormat (".00");
		
		// Create integers to store user input # of rows and columns
		int rows;
		int columns;

		// User prompts
		System.out.print ("How many rows in the array? ");
		rows = s.nextInt();
		System.out.print ("How many columns in the array? ");
		columns = s.nextInt();
		
		// Create Multidimensional array
		double [][] array2d = new double [rows][columns];
		
		// Generate random numbers to fill array 
		for (int i = 0; i < array2d.length; i++){
			
			for (int j = 0; j < array2d[i].length; j++){
				
				array2d[i][j] = Math.random() * 100;
           // Fill array with decimal numbers between 0 and 100 
			}
		}
		System.out.print ("\nThis 2D array contains: \n");
		
		for (int k = 0; k < array2d.length; k++){
			for (int l = 0; l < array2d[k].length; l++){		
				System.out.print (oneplaces.format(array2d[k][l]) + ", ");
                // Print 2D array of rows and columns
			}
			System.out.println ();
           // Organize array into a chart 
		}
		
		System.out.println ("\nConverted to a 1D array: ");
		
		int count = 0; // Create counter variables
		int count2 = 0;
		
		for (int m = 0; m < array2d.length; m++){
           // Determine length of 2D array
			count += array2d[m].length;
		}
	
			double [] array1d = new double[count];
          // Initialize 1D array
	
			for (int m = 0; m < array2d.length; m++){
				System.arraycopy (array2d[m], 0, array1d, count2, array2d[m].length);
                // Copy 2D array's contents to 1D array elements
				count2 += array2d[m].length;
				System.out.print (oneplaces.format(array1d[m]) + ", ");
               // Print out 1d array with 2d array's variables
			}
	}	
}

I am really close to finishing this program and my output is almost there, except it's only printing out the first half or so of the array. I have two for loops and two counters to determine the size of the array and then copy the multidimensional array's values into the 1D array, but it only prints out the first half of the array as such:

How many rows in the array? 4
How many columns in the array? 2

This 2D array contains:
35.23, 26.94,
99.48, 66.69,
7.31, 25.18,
64.53, 21.25,

Converted to a 1D array:
35.23, 26.94, 99.48, 66.69,

And yes, I realize that I should be formatting my Print statements with % but my instructor doesn't seem to care about it (he never taught it to us) so for the time being I am being stubborn and using \.

[Liutauras Vilda]

Lets assume it's correct up to line 56. Overcomplicated from line 59. Look for easier solution (I found it for myself).
Also, check Line 60 (your comment and actual taken action).

[Henry Wong]

Seth Lamb wrote:
I am really close to finishing this program and my output is almost there, except it's only printing out the first half or so of the array. I have two for loops and two counters to determine the size of the array and then copy the multidimensional array's values into the 1D array, but it only prints out the first half of the array as such:

You iterate through each "row" of the "two dimensional" array and ...

1. Copy one row of the "2D" array into the "one dimensional" array ... looks good.
2. Calculate the new index of the "one dimensional" array ... looks good.

3. Print one value of the "one dimensional" array... huh?? You just copied a whole row, so how does printing one value represent the whole row the you just copied?
3b. To print the one value, you used the m index on the "one dimensional" array ... huh?? Isn't the m index used to dereference a row of the "2D" array? How can it now be applied to the "1D" array?

[EDIT] Oops. Didn't noticed that Liutauras had already answered with a hint (which is probably better as it makes the OP think it through). Sorry. Have a cow ...

Henry

[Liutauras Vilda]

Thank you, Henry

I still think, I didn't express myself clear enough after 3 times editing my post.

Seth Lamb, did you find where your mistake appeared?

[Campbell Ritchie]

Please don't write such long lines; I have corrected that by moving the comments to lines by themselves. You don't need so many comments. We know that you are creating objects without having to be told that, so you can probably delete most of those comments.

The big problem that I can see is that you are trying to do everything in the main method. You should have one statement in the main method and everything else in different methods. You should have a method which creates your array, one to print it, etc., etc. Then you can test the methods separately and find which works and which doesn't.

And there is no need to be rude about your instructor.