#30 jagged and 3D Array in Java

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In this lecture we are discussing:
1)What if array of array of different size ?
2)Jagged array concept
3)If i donot know column size of array
4)traverse the array using for loop and enhance loop

#1
Suppose we want to create a 2d dimensional array such that it has
5 rows but we donot know for each row we need different size for column.
for that we go for array of array of different size

-------------
| 1 | 2 | 3 |
---------------------
| 4 | 5 | 6 | 7 | 8 |
-------------------------
| 1 | 5 | 9 | 2 | 4 | 7 |
-------------------------

in above diagram we have three rows and first row has 3 elements
second row has 5 elements and third row has 6 elements.

#2#3
jagged array concept come in java 8
-- Jagged array is a multidimensional array where member arrays are of different size. For example, we can
create a 2D array where first array is of 3 elements, and is of 4 elements. Following is the example demonstrating
the concept of jagged array.

syntax to create --

int nums[][]=new int[3][];
nums[0] =new int[3];
nums[1] =new int[5];
nums[2] =new int[6];

initalize value in array using random()method present in Math class
for(int j=0;j nums[i].length;j++){
}
}
#5
Traverse using for loop :
for(int j=0;j nums[i].length;j++){
}
}

Traverse using enhanced for loop:
for(int x[]:nums){
for(int y:x){
}
}

Note: Just like 2-d jagged array we can create 3-d , 4-d jagged array
for cursoity:
int num[][][]=new int[3][][];
num[0]=new int[2][];
num[1]=new int[3][];
num[2]=new int[4][];
num[0][0]=new int[2];
num[0][1]=new int[3];
num[1][0]=new int[4];
num[1][1]=new int[5];
num[1][2]=new int[6];
num[2][0]=new int[7];
num[2][1]=new int[8];
num[2][2]=new int[9];
num[2][3]=new int[10];

Intialize the array:
for(int j=0;j num[i].length;j++){
for(int k=0;k num[i][j].length;k++){
}
}
}

Traverse the element of array:
for(int j=0;j num[i].length;j++){
for(int k=0;k num[i][j].length;k++){
}
}
}

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[ayashazhar]

had a hard time finding a proper video on jagged array and how to update it . thanks bro

[sherislam]

You are amazing Telusku, the way you have explained the concept of Array, You deserve appreciation.You nailed it bro👏❣

[DevilGaming-blog]

In first for loop instead of i<nums.length we can write the no of rows ( I.e 3) bcoz here no of rows are fixed.

[IshmaelSmart-lv]

I like the way you explain Boss, thanks 😊😊

[balapraveen]

Can we do jagged array of 2nd dimension in 3 dimensional array?

[SowjanyaKadiveti]

i had tried much more complex one three arrays
class demo
{
public static void main(String[] args)
{
int num[][][]= new int[3][2][];
num[0][0]= new int[10];
num[0][1]= new int[6];
num[1][0]= new int[2];
num[1][1]= new int [5];
num[2][0]=new int[8];
num[2][1]=new int[8];

for(int i=0;i<num.length;i++)
{
for (int j = 0; j <num[i].length; j++)
{
for (int k=0; k<num[i][j].length;k++)
{
num[i][j][k]= (int)(int)(Math.random() * 100);
}


}

}




for(int n[][]:num)
{
for(int m[]:n)
{
for(int l:m)
{
System.out.print(l+" ");
}
System.out.println();
}
}
}
}

and i got this out put

50 6 45 32 72 96 7 49 39 51
64 4 11 78 79 77
87 43
97 54 40 59 82
86 28 31 67 62 6 51 92
13 34 64 59 32 36 17 46

[anilkumargangarapu]

hii, how can we assign fixed values of our own to arrays with different sizes,

[AdhilMhmdVK]

Three dimensional array with proper example...i couldnt understand this one.

[purnimanaskar]

// Online Java Compiler
// Use this editor to write, compile and run your Java code online
public class Demo {

public static void main(String[] args)

{


int nums[][][]=new int [3][4][5]; // three dimensional

for(int i=0;i<nums.length;i++)
{
for(int j=0;j<nums[i].length;j++)
{
for(int k=0;k<nums[i][j].length;k++){

}
}

}
for(int i=0;i<nums.length;i++){
for(int j=0;j<nums[i].length;j++){
for(int k=0;k<nums[i][j].length;k++){
System.out.print(nums[i][j]+" ");
}
}

}
}
}
This is the code for 3D array...

[RameshMaity]

public class Array {
public static void main(String[] args) {
int num1[]=new int[3];
int num[][]=new int[3][4];
for(int i=0;i<3;i++){
num1[i] = (int) (Math.random() * 10);
for(int j=0;j<4;j++){

}
}
System.out.println("\nTwo dimensitonal Array");

for (int i = 0; i < 3; i++) {
for (int j = 0; j < 4; j++) {
System.out.print(num[i][j]+" ");
}
System.out.println();
}
System.out.println("One dimensitonal Array");
for(int n:num1){
System.out.print(n+" ");
}
System.out.println("\nTwo dimensitonal Array");
for(int n[]:num){
for(int m:n)
System.out.print(m+" ");
System.out.println();
}
int num2[][]=new int[4][];//jagged array
num2[0]=new int[2];
num2[1]=new int[3];
num2[2]=new int[4];
num2[3] = new int[5];
for(int i=0;i<4;i++){
for(int j=0;j<num2[i].length;j++){

}
}
System.out.println("Jagged Array");
for (int n2[] : num2) {
for (int m2 : n2) {
System.out.print(m2+" ");
}
System.out.println();
}
System.out.println("3D Array");
int num3[][][]=new int[3][2][2];
for(int i=0;i<3;i++){
for(int j=0;j<2;j++){
for(int k=0;k<2;k++){
num3[i][j][k]= (int) (Math.random() * 10);

}
}
}
System.out.println();
for(int n3[][]:num3){
for(int n31[]:n3){
for(int n311:n31)
System.out.print(n311+" ");
}
System.out.println();
}

}
}

[puruagni]

Why are you not updating VS Code? Please update VS Code.

[thelivereactions]

This video cant understand, where does math & *10 come from!