how to know if array contains a value that is given

Question

Hello I am trying to figure out how arrays work and now i am created a class that looks for a integer in a class but i think i've done something work.. especially the method convert is wrong i think.. it has to search in the array if the array index contains that value and if so print that out but it doesn't work can someone explain the logics and how to solve it? ( with an example if possible )

thanks in advance! below you can see my code:

package h05UitgeschrevenGetal;
import java.awt.event.*;
import java.util.Random;
import javax.swing.*;
public class GetalConverter extends JPanel implements ActionListener {
private JLabel getal;
private JTextField invoer, uitvoer;
private int invoerWaarde;
private JButton converteer;
String[] klein = new String[20];
String[] groot = new String[10];
public GetalConverter() {
 getal = new JLabel("geef een geheel getal");
 add(getal);
 invoer = new JTextField(7);
 invoer.addActionListener(this);
 add(invoer);
 converteer = new JButton("In woorden");
 converteer.addActionListener(this);
 add(converteer);
 uitvoer = new JTextField(7);
 uitvoer.setEditable(false);
 add(uitvoer);
 klein[0] = "nul";
 klein[1] = "een";
 klein[2] = "twee";
 klein[3] = "drie";
 klein[4] = "vier";
 klein[5] = "vijf";
 klein[6] = "zes";
 klein[7] = "zeven";
 klein[8] = "acht";
 klein[9] = "negen";
 klein[10] = "tien";
 klein[11] = "elf";
 klein[12] = "twaalf";
 klein[13] = "dertien";
 klein[14] = "veertien";
 klein[15] = "vijftien";
 klein[16] = "zestien";
 klein[17] = "zeventien";
 klein[18] = "achtien";
 klein[19] = "negentien";
 groot[1] = "tien";
 groot[2] = "twintig";
 groot[3] = "dertig";
 groot[4] = "veertig";
 groot[5] = "vijftig";
 groot[6] = "zestig";
 groot[7] = "zeventig";
 groot[8] = "tachtig";
 groot[9] = "negentig";
}
public void setValue(int val) {
 invoerWaarde = val;
 //System.out.println(invoerWaarde);
}
public int getValue() {
 return invoerWaarde;
}
public void convert() {
 // here comes the converting code
}
@Override
public void actionPerformed(ActionEvent e) {
 setValue(Integer.parseInt(invoer.getText()));
 convert();
 //System.out.println(invoerWaarde);
}
}

Answer 1

You have defined your array as: -

String[] strings = new String[klein];

Now, when you are invoking contains method: -

Arrays.asList(strings).contains(waar)

You are actually checking for the containment of an integer in an ArrayList of type String. Since, waar is an integer you passed in your convert method. How do you expect it to return a true value?

it has to search in the array if the array index contains that value

For that case, you need to pass that value to your convert method. You are rather passing index.

I guess you want something like this: -

public void convert(String value) {
 for (int i = 0; i < strings.length; i++) {
 if (strings[i].equals(value)) {
 System.out.println("Value: " + strings[i]);
 System.out.println("Index: " + i);
 }
 }
}

• Reshad: ye i tought of something like that already ... but how can i look to the "index" ?
• Rohit Jain: @Reshad. But you are passing an integer value. Whose index you want to fetch?
• Reshad: no that is not possible since the value for convert is an integer.. not a string i am trying to create something that converts 1 into one and 200 into two hundred for example
• Rohit Jain: @Reshad. OK. Then how would you compare 1 and one?
• Reshad: Well that is my problem.. but another problem I just noticed is my array has to be like written out ( atleast the values ) because now i have this loop that goes up by 1 each time.. but nothing goes into the value like value[1] = "one" so i have to write it out right?

Answer 2

String findValue = ...;
for(String str: strs){
 if(str.equals(findValue)){
 return true;
 }
}

if you are looking for index -

public void convert(Integer waar) {
 for(int index=0;index<strs.length;index++){
 if(strs[index].equals(String.valueOf(waar))){
 System.out.println("index -> "+index);
 }
 }
}

• Reshad: ah the second example is what i needed! could you know by accident also how to print the value of the index when found?
• Subhrajyoti Majumder: print the value of the index you can put just into Sysout(i);

Answer 3

I know for a fact, that from the code given above, your program will only work in the range of 0 to 99. Try this code out:

public void Convert()
{
 int grootVal, kleinVal;
 if(invoerWaarde < 100){
 //ok, possibility of finding it in the array.
 grootVal = (int)Math.floor(invoerWaarde / 10.0)
 kleinVal = invoerWaarde - (grootVal * 10);
 try{
 String valueString = groot[grootVal] + " " + klein[kleinVal];
 System.out.println(valueString);
 }catch(ArrayOutOfBoundsException aoobe){
 System.out.println("");
 }
 }
}

• Reshad: it works for the most values but not for every one unfortunately but with a little bit modification it will i hope!
• Reshad: 10 and below 10, i think it needs some if statements because it says the 0 even if the 0 does not exist in that number for example 5 is becoming zero five instead of just five etc..
• Aniket Inge: what is becoming 0 when 0 doesn't exist?