How can I have an access to array elements from array of arrays?

Question

Int a1= {1,2};int a2= {2,3}; int a3 [] [] = {a1,a2}; int r=(int) (Math.random() *a3.length); how can I have access to that a3 [r] stored in another array? Like-for (int p:a3[r]) {

SOP(p);

} how can I access p [0], p[1],only in Java.

Answer 1

It sounds like you want to randomly access the elements of the 2 x 2 array.....

you need to generate TWO random indices. Here is some code. You can run it

as many times as you want. It took several times, but index (1,1) did come out..

import java.io.*;

class Array2D

{

public static void main(String args[])

{

int N=2;

int [][] A;

int [] b1 = {1,2};

int [] b2 = {2,3};

A= new int [2][2];

A[0] = new int[2];

A[1] = new int[2];

A[0] = b1;

A[1] = b2;

boolean done_flag = false;

Console console = System.console();

while (!done_flag)

{

/************************************************

//generates a random number between 1 and 100;

// if less than 50, random index is zero;

// otherwise it is ONE (1)

****************************************************/

double randomNum = Math.random() * 99+1;

int randIndex1 = (randomNum<50) ? 1 : 0;

randomNum = Math.random() * 99+1;

int randIndex2 = (randomNum<50) ? 1 : 0;

System.out.println(" random index 1 = " + randIndex1);

System.out.println(" random index 2 = " + randIndex2);

System.out.println(" the array element is " + A[randIndex1][randIndex2]);

try

{

System.out.print(" Do It again ???? input 1 = Yes 0 = No :> ");

String inbuff = console.readLine();

int response = Integer.parseInt(inbuff);

done_flag = (response==0) ? true : false;

}

catch (Exception ex) { System.err.println(" input error "); continue; };

} //while

} //main

} //class