How to check if array indexes are empty and if so check the next?

Question

Anybody got any idea on how I can check if an array indexes(not just one index) are empty and if is empty or zero put a value there. And also if all the indexes are all not empty print an error.

Sorry unfortunately I can't give rep.

import java.util.Scanner; 

public class Myhash {

/**
 * @param args
 */
public static void main(String[] args) {
    // TODO Auto-generated method stub

    int [] myData = new int[17]; 

    int [] newData = new int [17];

    System.out.println("Please enter 16 integer numbers");
    for(int i= 0; i<myData.length; i++){
        //System.out.print("Please enter 16 numbers");
        Scanner input = new Scanner(System.in);
        int data =input.nextInt(); 
        myData[i]=data; 
        int num3 = data % 17;
        newData[num3]=data; 
    }       

    System.out.println("These are the numbers you entered\n");      
    System.out.printf("%s%8s \n", "Index", "Value"); 

    for(int t=0; t<myData.length; t++){
        System.out.printf("%5d%8d\n", t, myData[t]);
    }

    System.out.println("\n");
    System.out.println("The Hash Function:\n\n");
    System.out.printf("%5s%8s \n", "Index", "Value"); 

            for(int s=0; s<newData.length; s++){
        System.out.printf("%5d%8d\n", s, newData[s]);
            }   
    }
}

on here:

    for(int s=0; s<newData.length; s++){
    System.out.printf("%5d%8d\n", s, newData[s]);
    }

how do check for more than one index(if empty? If the index is empty how do check for the next index and if that one is not empty how do i check the next one, etc?

arrays of int by default has all zero values. So if element is zero it has not been set or it has been set to zero :) — Andrzej Jozwik, Mar 20 '12 at 11:35
I can't figure this out: If the index is empty how do check for the next index and if that one is not empty how do i check the next one, etc? as ajozwik said, if is zero then is considered empty because is an int — user1244123, Mar 20 '12 at 11:48

score 11 · Answer 1 · answered Mar 20 '12 at 21:22

Elements in primitive arrays can't be empty. They'll always get initialized to something

If you declare the array like so

 int [] newData = new int [17];

then all of the elements will default to zero.

For checking if an element is not entered, you can use a simple loop :

 for(int i=0;i<newData.length;i++)
    {
        if(newData[i]==0)
            System.out.println("The value at " + i + "is empty");
    }

Although , the above code will not work in your case, because the user might enter 0 as an input value and still this code will consider it to be empty.

What you can do is, initialize the array with all values as -1, and specify at the input prompt that only values >=0 can be entered . The initialization can be done like this:

int[] newData = new int[17];
for(int i=0;i<newData.length;i++)
{
   newData[i]= -1;   
}

Then you can ask the user for input and do the processing. Then you can use this:

for(int i=0;i<newData.length;i++)
    {
        if(newData[i]==-1)
           System.out.println("The value at " + i + "is empty");
    }

score 2 · Answer 2 · answered Mar 20 '12 at 12:03

2

Here:

for(int i = 0; i < array.length; i++)
{
    if(array[i] == null)
        continue;
}

answered Mar 20 '12 at 12:03

Liam Haworth

848
1
9
27

3

You have to explain more. This is basically a code-only answer. – Wulf Jun 12 '13 at 04:07

How to check if array indexes are empty and if so check the next?

2 Answers2

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