ConcurrentLinkedDeque removeFirst() method in Java
Last Updated :
18 Sep, 2018
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The ConcurrentLinkedDeque.removeFirst() is an in-built function in Java which removes the first element from the deque container. The function throws a NoSuchElementException if this deque is empty.
Syntax:
Java
Java
Conn_Linked_Deque.removeFirst()Parameters: The function does not accepts any parameter. Return Values: The function returns the first element in the deque. Exception: The function throws a NoSuchElementException if this deque is empty. Below program illustrates the removeFirst() method: Program 1: This program involves deque with Integer elements.
// Java Program to demonstrate removeFirst()
// method of ConcurrentLinkedDeque
import java.util.concurrent.*;
class ConcurrentLinkedDequeDemo {
public static void main(String[] args)
{
ConcurrentLinkedDeque<Integer> cld =
new ConcurrentLinkedDeque<Integer>();
cld.addFirst(12);
cld.addFirst(70);
cld.addFirst(1009);
cld.addFirst(475);
// Displaying the existing LinkedDeque
System.out.println("Elements in"
+ "the LinkedDeque: " + cld);
// Display the first element
System.out.println("Element removed : "
+ cld.peekFirst());
// Remove the first element
cld.removeFirst();
// Displaying the elements
System.out.println("Elements in"
+ "the LinkedDeque: " + cld);
}
}
// Java Program to demonstrate removeFirst() // method of ConcurrentLinkedDeque import java.util.concurrent.*;class ConcurrentLinkedDequeDemo { public static void main(String[] args) { ConcurrentLinkedDeque<Integer> cld = new ConcurrentLinkedDeque<Integer>(); cld.addFirst(12); cld.addFirst(70); cld.addFirst(1009); cld.addFirst(475); // Displaying the existing LinkedDeque System.out.println("Elements in" + "the LinkedDeque: " + cld); // Display the first element System.out.println("Element removed : " + cld.peekFirst()); // Remove the first element cld.removeFirst(); // Displaying the elements System.out.println("Elements in" + "the LinkedDeque: " + cld); }}
Output:
Program 2: This program involves deque with String elements.
Elements inthe LinkedDeque: [475, 1009, 70, 12] Element removed : 475 Elements inthe LinkedDeque: [1009, 70, 12]
// Java Program Demonstrate removeFirst()
// method of ConcurrentLinkedDeque
import java.util.concurrent.*;
class ConcurrentLinkedDequeDemo {
public static void main(String[] args)
{
ConcurrentLinkedDeque<String> cld =
new ConcurrentLinkedDeque<String>();
cld.addFirst("GFG");
cld.addFirst("Gfg");
cld.addFirst("GeeksforGeeks");
cld.addFirst("Geeks");
// Displaying the existing LinkedDeque
System.out.println("Elements in"
+ "the LinkedDeque: " + cld);
// Display the first element
System.out.println("Element removed : "
+ cld.peekFirst());
// Remove the first element
cld.removeFirst();
// Displaying the elements
System.out.println("Elements in"
+ "the LinkedDeque: " + cld);
}
}
// Java Program Demonstrate removeFirst() // method of ConcurrentLinkedDeque import java.util.concurrent.*;class ConcurrentLinkedDequeDemo { public static void main(String[] args) { ConcurrentLinkedDeque<String> cld = new ConcurrentLinkedDeque<String>(); cld.addFirst("GFG"); cld.addFirst("Gfg"); cld.addFirst("GeeksforGeeks"); cld.addFirst("Geeks"); // Displaying the existing LinkedDeque System.out.println("Elements in" + "the LinkedDeque: " + cld); // Display the first element System.out.println("Element removed : " + cld.peekFirst()); // Remove the first element cld.removeFirst(); // Displaying the elements System.out.println("Elements in" + "the LinkedDeque: " + cld); }}
Output:
Reference: https://docs.oracle.com/javase/8/docs/api/java/util/concurrent/ConcurrentLinkedDeque.html#removeFirst()
Elements inthe LinkedDeque: [Geeks, GeeksforGeeks, Gfg, GFG] Element removed : Geeks Elements inthe LinkedDeque: [GeeksforGeeks, Gfg, GFG]
