# Linked List - Insert a new node at the start

In this method, a new node is inserted at the beginning of the linked list. For example - if the given List is 10->20->30 and a new element 100 is added at the start, the Linked List becomes 100->10->20->30.

Inserting a new node at the beginning of the Linked List is very easy. First, a new node with given element is created. It is then added before the head of the given Linked List that makes the newly added node to new head of the Linked List by changing the head pointer to point to the new node. The function push_front is created for this purpose. It is a 4-step process.

```void push_front(int newElement) {

//1. allocate a new node
Node* newNode = new Node();

//2. assign data element
newNode->data = newElement;

//3. make next node of new node as head

//4. make new node as head
}
```
```void push_front(struct Node** head_ref, int newElement) {

//1. allocate a new node
struct Node* newNode;
newNode = (struct Node*)malloc(sizeof(struct Node));

//2. assign data element
newNode->data = newElement;

//3. make next node of new node as head

//4. make new node as head
}
```
```def push_front(self, newElement):

#1 & 2. allocate a new node
#       and assign data element
newNode = Node(newElement)

#3. make next node of new node as head

#4. make new node as head
```
```void push_front(int newElement) {

//1. allocate a new node
Node newNode = new Node();

//2. assign data element
newNode.data = newElement;

//3. make next node of new node as head

//4. make new node as head
}
```
```public void push_front(int newElement) {

//1. allocate a new node
Node newNode = new Node();

//2. assign data element
newNode.data = newElement;

//3. make next node of new node as head

//4. make new node as head
}
```
```public function push_front(\$newElement) {

//1. allocate a new node
\$newNode = new Node();

//2. assign data element
\$newNode->data = \$newElement;

//3. make next node of new node as head

//4. make new node as head
}
```

The below is a complete program that uses above discussed concept to insert new node at the start of the linked list.

```#include <iostream>
using namespace std;

//node structure
struct Node {
int data;
Node* next;
};

private:
public:
}

//Add new element at the start of the list
void push_front(int newElement) {
Node* newNode = new Node();
newNode->data = newElement;
}

//display the content of the list
void PrintList() {
if(temp != NULL) {
cout<<"The list contains: ";
while(temp != NULL) {
cout<<temp->data<<" ";
temp = temp->next;
}
cout<<"\n";
} else {
cout<<"The list is empty.\n";
}
}
};

// test the code
int main() {

//Add three elements at the start of the list.
MyList.push_front(10);
MyList.push_front(20);
MyList.push_front(30);
MyList.PrintList();

return 0;
}
```

The above code will give the following output:

```The list contains: 30 20 10
```
```#include <stdio.h>
#include <stdlib.h>

//node structure
struct Node {
int data;
struct Node* next;
};

//Add new element at the start of the list
void push_front(struct Node** head_ref, int newElement) {
struct Node* newNode;
newNode = (struct Node*)malloc(sizeof(struct Node));
newNode->data = newElement;
}

//display the content of the list
printf("The list contains: ");
while (temp != NULL) {
printf("%i ",temp->data);
temp = temp->next;
}
printf("\n");
} else {
printf("The list is empty.\n");
}
}

// test the code
int main() {
struct Node* MyList = NULL;

//Add three elements at the start of the list.
push_front(&MyList, 10);
push_front(&MyList, 20);
push_front(&MyList, 30);
PrintList(MyList);

return 0;
}
```

The above code will give the following output:

```The list contains: 30 20 10
```
```# node structure
class Node:
def __init__(self, data):
self.data = data
self.next = None

def __init__(self):

#Add new element at the start of the list
def push_front(self, newElement):
newNode = Node(newElement)

#display the content of the list
def PrintList(self):
if(temp != None):
print("The list contains:", end=" ")
while (temp != None):
print(temp.data, end=" ")
temp = temp.next
print()
else:
print("The list is empty.")

# test the code

#Add three elements at the start of the list.
MyList.push_front(10)
MyList.push_front(20)
MyList.push_front(30)
MyList.PrintList()
```

The above code will give the following output:

```The list contains: 30 20 10
```
```//node structure
class Node {
int data;
Node next;
};

}

//Add new element at the start of the list
void push_front(int newElement) {
Node newNode = new Node();
newNode.data = newElement;
}

//display the content of the list
void PrintList() {
Node temp = new Node();
if(temp != null) {
System.out.print("The list contains: ");
while(temp != null) {
System.out.print(temp.data + " ");
temp = temp.next;
}
System.out.println();
} else {
System.out.println("The list is empty.");
}
}
};

// test the code
public class Implementation {
public static void main(String[] args) {

//Add three elements at the start of the list.
MyList.push_front(10);
MyList.push_front(20);
MyList.push_front(30);
MyList.PrintList();
}
}
```

The above code will give the following output:

```The list contains: 30 20 10
```
```using System;

//node structure
class Node {
public int data;
public Node next;
};

}

//Add new element at the start of the list
public void push_front(int newElement) {
Node newNode = new Node();
newNode.data = newElement;
}

//display the content of the list
public void PrintList() {
Node temp = new Node();
if(temp != null) {
Console.Write("The list contains: ");
while(temp != null) {
Console.Write(temp.data + " ");
temp = temp.next;
}
Console.WriteLine();
} else {
Console.WriteLine("The list is empty.");
}
}
};

// test the code
class Implementation {
static void Main(string[] args) {

//Add three elements at the start of the list.
MyList.push_front(10);
MyList.push_front(20);
MyList.push_front(30);
MyList.PrintList();
}
}
```

The above code will give the following output:

```The list contains: 30 20 10
```
```<?php
//node structure
class Node {
public \$data;
public \$next;
}

public function __construct(){
}

//Add element at the start of the list
public function push_front(\$newElement) {
\$newNode = new Node();
\$newNode->data = \$newElement;
}

//display the content of the list
public function PrintList() {
\$temp = new Node();
if(\$temp != null) {
echo "The list contains: ";
while(\$temp != null) {
echo \$temp->data." ";
\$temp = \$temp->next;
}
echo "\n";
} else {
echo "The list is empty.\n";
}
}
};

// test the code

//Add three elements at the start of the list.
\$MyList->push_front(10);
\$MyList->push_front(20);
\$MyList->push_front(30);
\$MyList->PrintList();
?>
```

The above code will give the following output:

```The list contains: 30 20 10
```

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