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Java

Posted by Jeremy Juengel
Jeremy Juengel
Courses Plus Student 5,286 Points

Does the essentially create a dynamic array?

import java.util.Scanner;

public class Arrays {

public static void main(String[] args){

    String[] myString = new String[0];
    String newFruit = "apple";
    Scanner scan = new Scanner(System.in);

    for (int i = 0; i < 10; i++)
    {
        // Prompt for new fruit
        System.out.print("\nEnter a new fruit: ");

        // Get new fruit from user
        newFruit = scan.nextLine();

        // Print out what is in the old array
        System.out.print("Value in old array is: ");
        printArray(myString);
        System.out.println();

        // Add new item to array
        String[] newString = addFruit(myString, newFruit);

        // Copy new array into old array
        myString = newString;

        // Print out the new array
        System.out.print("Value in new array is: ");
        printArray(newString);
        System.out.println("\n");
    }

    scan.close();

}


public static String[] addFruit(String[] currentArray, String newFruit){

    //check length of current string
    int currentLength = currentArray.length;

    //create new array with original length + 1;
    String[] newArray = new String[currentLength + 1];

    //copy old array into new array
    System.arraycopy(currentArray, 0, newArray, 0, currentLength);

    //add new item to end of array
    newArray[currentLength] = newFruit;

    return newArray;
}


public static void printArray(String[] myArray){

    for (String fruit : myArray ){
        System.out.print(fruit + " ");
    }
}

}

jcorum
jcorum
71,830 Points

Not sure what your goal is. I didn't test your work, but I'm sure you wouldn't have posted it if it doesn't work! And it does allow you to create new arrays that are larger than the original. But from a programming point of view the name of the array changes, and in many places where one would want to use a dynamic array that's a real drawback.

If your goal is to have a dynamic array, and not just an interesting programming problem, then they are already built-in to Java: ArrayLists. I have no idea how much Java you have, or whether this is old news or not. Just saying, why do all that when you can just create an ArrayList<String>?