Dynamic Arrays 🌱

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Dynamic arrays arraylists tutorial example explained
Part 1 (00:00:00) theory
Part 2 (00:05:00) practice

#dynamic #arrays #arraylists

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Комментарии

I forgot to add a get() method for random access 🤦‍♂️
I've included that in the code posted here...

public class Main{

public static void main(String[] args) {

DynamicArray dynamicArray = new DynamicArray(5);

dynamicArray.add("A");
dynamicArray.add("B");
dynamicArray.add("C");

//dynamicArray.insert(0, "X");

System.out.println("size: " + dynamicArray.size);
" + dynamicArray.capacity);
System.out.println("empty: " + dynamicArray.isEmpty());
}
}
public class DynamicArray {

int size;
int capacity = 10;
Object[] array;

public DynamicArray() {
this.array = new Object[capacity];
}
public DynamicArray(int capacity) {
this.capacity = capacity;
this.array = new Object[capacity];
}

public Object get(int index) {
return array[index];
}

public void add(Object data) {

if(size >= capacity) {
grow();
}
array[size] = data;
size++;
}

public void insert(int index, Object data) {

if(size >= capacity) {
grow();
}
for(int i = size; i > index; i--) {
array[i] = array[i - 1];
}
array[index] = data;
size++;
}

public void delete(Object data) {

for(int i = 0; i < size; i++) {
if(array[i] == data) {
for(int j = 0; j < (size - i - 1); j++){
+ j] = array[i + j + 1];
}
array[size - 1] = null;
size--;
if(size <=(int) (capacity/3)) {

}
break;
}
}
}

public int search(Object data) {

for(int i = 0; i < size; i++) {
if(array[i] == data) {
return i;
}
}
return -1;
}

private void grow() {

int newCapacity = (int)(capacity * 2);
Object[] newArray = new Object[newCapacity];

for(int i = 0; i < size; i++) {
newArray[i] = array[i];
}
capacity = newCapacity;
array = newArray;
}

private void shrink() {

int newCapacity = (int)(capacity / 2);
Object[] newArray = new Object[newCapacity];

for(int i = 0; i < size; i++) {
newArray[i] = array[i];
}
capacity = newCapacity;
array = newArray;
}

public boolean isEmpty() {
return size == 0;
}

public String toString() {

String string = "";

for(int i = 0; i < capacity; i++) {
string += array[i] + ", ";
}
if(string != "") {
string = "[" + string.substring(0, string.length() - 2) + "]";
}
else {
string = "[]";
}
return string;
}
}

BroCodez

I hope you will continue this series. It's just amazing!

s.w.

Best videos on Data Structure & Algorithm. Thank you for making them!

BN-crel

This is so sick. Thank you for taking the time to explain and build a working ArrayList. I love people like you that explain things with both graphics and code. I have 0 questions about a topic when you put it together this organized. And the code in the comments (and the commented explanations)... 😙👌

MarshGames

great LECTURE.
still need to see this over again. love your lectures.

shaistakamran

What's the difference between making instantiating array as Object[] array and making the class able to hold generic objects using Java generics (i.e. public class DynamicArray<T>)? If we use Object[], wouldn't we have to cast elements to its actual type when retrieving them (e.g. int first = (int) array[0])?

SomduttaSomSinha

Can you make a video on Java Streams. I would really appreciate it ❤️

malekmousa

in the .toString() (assuming that you didn't use StringBuilder), wouldn't it be much more efficient and faster by using this?:

String string = "";

for(int i=0;i<size;i++){
if(i>0){
string += ", ";
}
string += array[i];
}

return "[" + string + "]";

instead of doing this?:

for(int i=0;i<size;i++){
string += array[i] + ", ";
}
if(!string.isEmpty()){
string = "["+ string.substring(0, string.length() - 2) + "]";
}
else{
string = "[]";
}

return string;

torekalanae_

Thank you so much for providing this enlighting tutorial.

phyusinlin

Currently having java as main programming language in my college, and your videos are really helpful. Thanks!

neil_armweak

hey brocode. Just a tip for your next videos. If you are going to import images in to your project is it possible to make a link in the descriptions to download the same objects? It's pretty annoying or even sometimes impossible to find an image with the same size etc...

just a tip
love ur videos:)
also make new java videos; if you got time;)

Daaninator

Yayy, Was waiting for it, your explanations are really great, thanks :)

AbhijeetKumar-cmjh

Hey bro this tutorial was long and BOOM THANKS BEEN HERE SINCE THE ROBOT SOUNDTRACK🤣

sihleeundefined

very glad to see your views increasing :) you deserve it and I'm happy that people finally found this gem.

conradpierce

I feel like in some instances with coding you just have to accept the information and be like well idk why but it works so it works for me? lol

dreful