如何将方法中随机生成的数字附加到数组中

Question

I've been trying for some hours now to get my class to work correctly. I'm trying to have a multidimensional array filled with random numbers created by my 'generateSample' method, then print the array.

public class GenerateUranium
{
int tray [][] = new int [5][3];
private int grading = 0;
private Random randomGenerator;

public GenerateUranium()
{
    randomGenerator = new Random();
}

public void generateSampleUranium()
{
    for (int i = 0; i < 5; i++)
    {
        for (int j = 0; j < 3; j++)
        {
            grading = randomGenerator.nextInt(50);
            printTray(tray);
        }
    }
}

public void printTray(int a[][])
{
   for( int row = 0 ; row < a.length ; row++) {
       for (int column = 0 ; column< a[row].length ; column++) {
           System.out.print(a[row][column]+"\t");
        }
   }
}
}    

I've tried following many examples on the Internet, but they're always for printing a specified array, not one being randomly generated by another method. So the trouble I'm having is linking the numbers created in the 'generateSample' to the array itself, so that I may successfully print them like so;

4 3 6

1 6 8

4 7 9

But as I have not been successful in linking my array between my methods for both adding to it and printing it, it is blank.

It's of last report I post for help, but any help would be greatly appreciated. Thanks.

Answer 1

Your generateSample method needs to actually write values into the array. Then, only after the entire 2D array is full, you should print it:

public void generateSample() {
    for (int i = 0; i < 5; i++) {
        for (int j = 0; j < 3; j++) {
            this.tray[i][j] = randomGenerator.nextInt(50);
        }
    }
    printTray(tray);
}

Answer 2

I've been trying for some hours now to get my class to work correctly. I'm trying to have a multidimensional array filled with random numbers created by my 'generateSample' method, then print the array.

public class GenerateUranium
{
int tray [][] = new int [5][3];
private int grading = 0;
private Random randomGenerator;

public GenerateUranium()
{
    randomGenerator = new Random();
}

public void generateSampleUranium()
{
    for (int i = 0; i < 5; i++)
    {
        for (int j = 0; j < 3; j++)
        {
            grading = randomGenerator.nextInt(50);
            printTray(tray);
        }
    }
}

public void printTray(int a[][])
{
   for( int row = 0 ; row < a.length ; row++) {
       for (int column = 0 ; column< a[row].length ; column++) {
           System.out.print(a[row][column]+"\t");
        }
   }
}
}    

I've tried following many examples on the Internet, but they're always for printing a specified array, not one being randomly generated by another method. So the trouble I'm having is linking the numbers created in the 'generateSample' to the array itself, so that I may successfully print them like so;

4 3 6

1 6 8

4 7 9

But as I have not been successful in linking my array between my methods for both adding to it and printing it, it is blank.

It's of last report I post for help, but any help would be greatly appreciated. Thanks.