- Java.util Package Classes
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Java ArrayDeque push() Method
Description
The Java ArrayDeque push(E e) method pushes an element E onto the stack represented by this deque. Essentially it add the element at the front of the ArrayDeque object.
Declaration
Following is the declaration for java.util.ArrayDeque.push() method
public void push(E e)
Parameters
e − The element to be pushed in the deque.
Return Value
This method does not return any value.
Exception
NullPointerException − if the specified element is null.
Example 1
The following example shows the usage of Java ArrayDeque push(E) method. In this example, we're using integers. As first, we'll add some items to the deque using add() method and then using push() method, we'll add elements to the stack. Then we're adding more elements using add() method again and the print the arraydeque to check if insertions in the deque are in the order we desired.
package com.tutorialspoint; import java.util.ArrayDeque; import java.util.Deque; public class ArrayDequeDemo { public static void main(String[] args) { // create an empty array deque Deque<Integer> deque = new ArrayDeque<>(); // use add() method to add elements in the deque deque.add(4); deque.add(5); deque.add(6); // use push() method to add element at the front of the deque deque.push(3); deque.push(2); deque.push(1);//now, element 1 will be at the front // these elements will be added in continuation with deque.add(6) deque.add(7); deque.add(8); // let us print all the elements available in deque System.out.println("ArrayDeque = " + deque); } }
Output
Let us compile and run the above program, this will produce the following result −
ArrayDeque = [1, 2, 3, 4, 5, 6, 7, 8]
Example 2
The following example shows the usage of Java ArrayDeque push(E) method. In this example, we're using strings. As first, we'll add some items to the deque using add() method and then using push() method, we'll add elements to the stack. Then we're adding more elements using add() method again and the print the arraydeque to check if insertions in the deque are in the order we desired.
package com.tutorialspoint; import java.util.ArrayDeque; import java.util.Deque; public class ArrayDequeDemo { public static void main(String[] args) { // create an empty array deque Deque<String> deque = new ArrayDeque<>(); // use add() method to add elements in the deque deque.add("D"); deque.add("E"); deque.add("F"); // use push() method to add element to the stack deque.push("C"); deque.push("B"); deque.push("A");//now, element A will be at the front // these elements will be added in continuation with deque.add("F") deque.add("G"); deque.add("H"); // let us print all the elements available in deque System.out.println("ArrayDeque = " + deque); } }
Output
Let us compile and run the above program, this will produce the following result −
ArrayDeque = [A, B, C, D, E, F, G, H]
Example 3
The following example shows the usage of Java ArrayDeque push(E) method. In this example, we're using Student objects. As first, we'll add some items to the deque using add() method and then using push() method, we'll add elements to the front of the deque. Then we're adding more elements using add() method again and the print the arraydeque to check if insertions in the deque are in the order we desired.
package com.tutorialspoint; import java.util.ArrayDeque; import java.util.Deque; public class ArrayDequeDemo { public static void main(String[] args) { // create an empty array deque Deque<Student> deque = new ArrayDeque<>(); // use add() method to add elements in the deque deque.add(new Student(4, "Julie")); deque.add(new Student(5, "Robert")); deque.add(new Student(6, "Adam")); // use push() method to add element to the stack deque.push(new Student(3, "Rohan")); deque.push(new Student(2, "Sohan")); deque.push(new Student(1, "Mohan"));//now, Student 1 will be at the front // these elements will be added in continuation with deque.add(new Student(6, "Adam")) deque.add(new Student(7, "Ali")); deque.add(new Student(8, "Ahmad")); // let us print all the elements available in deque System.out.println("ArrayDeque = " + deque); } } class Student { int rollNo; String name; Student(int rollNo, String name){ this.rollNo = rollNo; this.name = name; } @Override public String toString() { return "[ " + this.rollNo + ", " + this.name + " ]"; } }
Output
Let us compile and run the above program, this will produce the following result −
ArrayDeque = [[ 1, Mohan ], [ 2, Sohan ], [ 3, Rohan ], [ 4, Julie ], [ 5, Robert ], [ 6, Adam ], [ 7, Ali ], [ 8, Ahmad ]]