AndroidSketchpad

Create an array of Int' and also create 2 variable that mentions above.

var ints = IntArray(10)
var head = 0
var tail = 0

Methods:
enqueue():
insert data in the tail position and increase the tail

fun enqueue(n: Int) {
    ints[tail] = n
    tail += 1
    println("Input:" + n)
}

dequeue():
get data from head position index from the array and increase the head

fun dequeue(): Int {
    val n = ints[head]
    head += 1
    return n
}

Empty check:
if head and tail is same then the stack is empty

val isEmpty: Boolean
        get() = head == tail

Now time for access data:
First, create the main method:

fun main(arg: Array<String>) {
}

enqueue():
just run a for loop from 0 to 10 and insert data

for (i in 0..9) {
     enqueue(i)
}

Output:

Input:0
Input:1
Input:2
Input:3
Input:4
Input:5
Input:6
Input:7
Input:8
Input:9

works fine.
dequeue()
run a while loop until the queue is empty

while (!isEmpty) {
    println("value: " + dequeue())
}

Output:

value: 0
value: 1
value: 2
value: 3
value: 4
value: 5
value: 6
value: 7
value: 8
value: 9

It's work fine.
That's is the basic queue implementation.
You can check this out on Github

Discussion about queue:
The uses of the basic queue are not huge. It has a very limited use.
Because it wastes memory.
For example, if the queue has the capacity of 100. Then at the beginning data inserted from zero, when we access data from one we can get that data from the zero position. After the head is also increased and the tail already increased. Imagine by this way at 99 position data is filled and we access data from the 99 potions. If we want to insert new data into the queue it shows you a warning, "hey! I am full, I can not take any new data". But already the previous position is empty and there is no way to insert new data in the queue. we can use the previous position. But it allocates the memory. This is obviously the waste of memory. see the picture for the more clear concept.

Queue Data structure

To fix this problem we use the circular queue

Circular Queue

In circular queue top position and the last position move around a circle. I will discuss circular queue in the next post.

Until then, stay happy and keep practicing.
Thank you for reading this post. 
Happy coding

You check Wikipedia for more.

Let's start:

create a new activity:(In my case, I named it: SearchActivity)

First jump into XML code-

Now I am starting where I left in the previous post.

Now we need to create other 2 XML file. (In our final settings we need 3 XML file, we already have done one.)

In a previous post, I  cover android settings with a single preference screen (Android App Settings with Preference Fragment Compat).

we create 3 screen that's are-

• General
• Backup 
• Advance