LinkedList<T>.RemoveFirst method is used to remove the node at the start of the LinkedList<T>.
Syntax:
public void RemoveFirst ();
Exception: The method throws InvalidOperationException if the LinkedList<T> is empty.
Below given are some examples to understand the implementation in a better way:
Example 1:
// C# code to remove the node at // the start of the LinkedList using System;
using System.Collections;
using System.Collections.Generic;
class GFG {
// Driver code
public static void Main()
{
// Creating a LinkedList of Strings
LinkedList<String> myList = new LinkedList<String>();
// Adding nodes in LinkedList
myList.AddLast( "A" );
myList.AddLast( "B" );
myList.AddLast( "C" );
myList.AddLast( "D" );
myList.AddLast( "E" );
// Displaying the nodes in LinkedList
Console.WriteLine( "The elements in LinkedList are : " );
foreach ( string str in myList)
{
Console.WriteLine(str);
}
// Removing the node at the start of LinkedList
myList.RemoveFirst();
// Displaying the nodes in LinkedList
Console.WriteLine( "The elements in LinkedList are : " );
foreach ( string str in myList)
{
Console.WriteLine(str);
}
}
} |
Output:
The elements in LinkedList are : A B C D E The elements in LinkedList are : B C D E
Example 2:
// C# code to remove the node at // the start of the LinkedList using System;
using System.Collections;
using System.Collections.Generic;
class GFG {
// Driver code
public static void Main()
{
// Creating a LinkedList of Integers
LinkedList< int > myList = new LinkedList< int >();
// Removing the node at the start of LinkedList
// This should raise "InvalidOperationException"
// as the LinkedList is empty
myList.RemoveFirst();
// Displaying the nodes in LinkedList
Console.WriteLine( "The elements in LinkedList are : " );
foreach ( int i in myList)
{
Console.WriteLine(i);
}
}
} |
Runtime Error:
Unhandled Exception:
System.InvalidOperationException: The LinkedList is empty.
Note: This method is an O(1) operation.
Reference: