Question

So here’s my problem. I have to write a program that will fill array with random numbers(and it’s ok), then it’s necessary to print only even index numbers or only odd value numbers(j). Tried like this but when i put if statement and it shows every even number (index and value-the second in array) so it wrong. What should i do so?

import java.util.Random;

public class Array {

public static void main(String[] args)
{
    int rows = 5;
    int colu = 2;
    
    Random r = new Random();
    
    int [][] array = new int [rows][colu];
    
    for(int row = 0; row < array.length; row++)
    {
        for(int col = 0; col < array[row].length; col++)
        {
            array[row][col] = r.nextInt(10);
        }
    }
    
    for(int i = 0; i < array.length; i++)
    {       
        for(int j = 0; j < array[i].length; j++)
        {
            if(array[i][j]%2 == 0){
            System.out.print(array[i][j] + " ");
            }

            }
        }
        System.out.println();
    }
}

Thanks

Answer 1

I’m going to take a stab at this but I’m not sure if I quite understand yet.

int array[][] = new int[row][col];
// ... populate the array with random numbers, works fine...

// Let's traverse the first column.
for (int i = 0; i < row; i++) {
    int value = array[i][0]; // col 0 means first column
    if (value % 2 == 0) {
        // ...
    }
}

// Let's traverse the second column.
for (int i = 0; i < row; i++) {
    int value = array[i][1]; // col 1 means second column
    // ...
}

Is this what you mean? If it is, do you see the pattern and how you could generalize this and make the code a bit smaller?