Java array.push

Introduction to Java array.push

In Java, the push is a method that adds elements in the stack, array, LinkedList, etc. An element can be added to the stack using the method Java.util.Stack.push(E el), and it will be added to the top. In the case of LinkedList, java.util.LinkedList. Push () method is used the push element to the top of the stack denoted by LinkedList, which is almost the same as the addFirst() method. Java.util.ArrayDeque.push(E el) method in ArrayDeque pushes the element into the top of the Deque. More details on each of them will be discussed in the following sections.

Syntax and Parameters

Let us see the syntax of the push method in a stack, LinkedList, and Deque.

1. Stack

Syntax:

STACK.push(E el)

• Parameters: Item el of the element type that has to be pushed to the stack.
• Return Value: The argument passed will be returned.

2. LinkedListObject

Syntax:

LinkedListObject.push(Object el)

• Parameters: Item el of an object type that has to be pushed to the stack.
• Return Type: No value will be returned.

3. ArrayDeque

Syntax:

Array_Deque.push(E el)

• Parameters: Item el of ArrayDeque type that has to be pushed to the stack.
• Return Value: No value will be returned.

How does the push method work in Java?

The push method works similarly in Stack, LinkedList, and Deque. The following steps can be performed for that.

1. Create a stack, LinkedList, or Deque based on the requirement.

Stack<String>s = new Stack<String>();
LinkedList<Integer>li = new LinkedList<>();
Deque<Integer>dq = new ArrayDeque<Integer>(8);

2. add elements to it using the push method.

s.push("A")
li.push(45)
dq.push(9)

Examples to Implement Java array.push

 Below are the examples of implementing Java array.push:

1. Java program to push elements of string type in a stack.

Code:

import java.util.*;
public class PushMethodExample
{
public static void main(String args[])
{
// create a stack
Stack<String> s = new Stack<String>();
s.push("Happy");
s.push("Sad");
s.push("Confused");
s.push("Tensed");
s.push("Mixed Emotions");
// Print elements in stack
System.out.println("Stack Elements: " + s);
// Push new elements
s.push("Emotions");
s.push("Exists");
// Stack after adding new elements
System.out.println("Stack after adding new elements " + s);
}
}

Output:

Explanation: First, create a stack s and add elements using the push() method. Then, print the stack and once again add the elements so that it can be checked whether elements are inserted or not. On executing the code, stack before adding new elements and after adding new elements can be displayed.

2. Java program to push elements of integer type in LinkedList.

Code:

import java.util.*;
public class PushMethodExample
{
public static void main(String args[])
{
// create a LinkedList
LinkedList<Integer> li = new LinkedList<>();
li.push(45);
li.push(90);
li.push(67);
li.push(33);
li.push(56);
// Print elements in LinkedList
System.out.println("LinkedList Elements: " + li);
// Push new elements
li.push(456);
li.push(678);
// LinkedList after adding new elements
System.out.println("LinkedList after adding new elements " + li);
}
}

Output:

Explanation: Create a LinkedList li and add elements of integer type using the push() method. Then, print the LinkedList and once again add the elements so that it can be checked whether elements are inserted or not. On executing the code, LinkedList before adding new elements and after adding new elements can be displayed.

3. Java program to add integer elements to stack.

Code:

import java.util.*;
public class PushMethodExample
{
public static void main(String args[])
{
// create a stack
Stack<Integer> s = new Stack<Integer>();
s.push(45);
s.push(90);
s.push(67);
s.push(33);
s.push(56);
// Print elements in stack
System.out.println("stack Elements: " + s);
// Push new elements
s.push(456);
s.push(678);
// stack after adding new elements
System.out.println("stack after adding new elements " + s);
} }

Output:

Explanation: A stack to accept integer elements is created first. Once it is created, elements are added to the stack using the push() method. After printing the current elements in the stack, two new elements are also added to it. For checking whether those elements are also added to the stack, elements are printed one more time.  On executing the code, it can be seen that two more elements are also added to the stack.

4. Java program to add string elements to LinkedList.

Code:

import java.util.*;
public class PushMethodExample
{
public static void main(String args[])
{
// create a LinkedList
LinkedList<String> li = new LinkedList<>();
li.push("Happy");
li.push("Sad");
li.push("Confused");
li.push("Tensed");
li.push("Mixed Emotions");
// Print elements in LinkedList
System.out.println("LinkedList Elements: " + li );
// Push new elements
li.push("Emotions");
li.push("Exists");
// LinkedList after adding new elements
System.out.println("LinkedList after adding new elements " + li );
} }

Output:

Explanation: Create a LinkedList li and add elements of string type using the push() method. Then, print the LinkedList and once again add the elements so that it can be checked whether elements are inserted or not. On executing the code, LinkedList before adding new elements and after adding new elements can be displayed.

5. Java program to add integer elements to Deque.

Code:

import java.util.ArrayDeque;
import java.util.Deque;
public class PushMethodExample {
public static void main(String[] args) {
// Create ArrayDeque
Deque<Integer> dq = new ArrayDeque<Integer>(8);
// Add elements to the deque using add() method
dq.add(23);
dq.add(56);
dq.add(78);
dq.add(13);
// Print elements in deque
System.out.println("Elements in deque are : ");
for (Integer n : dq)
{
System.out.println("No : " + n);
}
// Add new elements using the method push()
dq.push(456);
dq.push(3432);
// Print elements in Deque after inserting new elements
System.out.println("Deque after inserting new elements:");
for (Integer n : dq)
{
System.out.println("No : " + n);
}
}
}

Output:

Explanation: Create a deque for adding the elements. For that, use the method push() and add the elements of integer type. Then, print the Deque and identify the current elements present in it. After printing the current elements in the stack, two new elements are also added to it. For checking whether those elements are also added to the Deque, elements are printed one more time.  On executing the code, it can be seen that two more elements are also added to the Deque.

Conclusion

Push is a method that is used to add elements in the stack, LinkedList, an array with the help of Java.util.Stack.push(E el), java.util.LinkedList.push() and Java.util.ArrayDeque.push(E el)  respectively. In this article, details such as syntax, working, and the push method are explained in detail.

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