# Circular Singly Linked List - Insert a new node at the start

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

Inserting a new node at the start of the circular singly linked list is very easy. First, a new node with given element is created. It is then added at the start of the list by linking the head node and last node to the new node.

The function push_front is created for this purpose. It is a 6-step process.

```void push_front(int newElement) {

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

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

//3. assign null to the next of new node
newNode->next = NULL;

//4. Check the list is empty or not,
//   if empty make the new node as head
} else {

//5. Else, traverse to the last node
temp = temp->next;

temp->next = newNode;
}
}
```
```void push_front(struct Node** head_ref, int newElement) {

//1. allocate node
struct Node *newNode, *temp;
newNode = (struct Node*)malloc(sizeof(struct Node));

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

//3. assign null to the next of new node
newNode->next = NULL;

//4. Check the list is empty or not,
//   if empty make the new node as head
} else {

//5. Else, traverse to the last node
temp = temp->next;
}

temp->next = newNode;
}
}
```
```def push_front(self, newElement):

#1 & 2 & 3. allocate node, assign data element
#          assign null to the next of new node
newNode = Node(newElement)

#4. Check the list is empty or not,
#   if empty make the new node as head
return
else:

#5. Else, traverse to the last node
temp = temp.next

temp.next = newNode
```
```void push_front(int newElement) {

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

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

//3. assign null to the next of new node
newNode.next = null;

//4. Check the list is empty or not,
//   if empty make the new node as head
} else {

//5. Else, traverse to the last node
Node temp = new Node();
temp = temp.next;

temp.next = newNode;
}
}
```
```public void push_front(int newElement) {

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

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

//3. assign null to the next of new node
newNode.next = null;

//4. Check the list is empty or not,
//   if empty make the new node as head
} else {

//5. Else, traverse to the last node
Node temp = new Node();
temp = temp.next;

temp.next = newNode;
}
}
```
```public function push_front(\$newElement) {

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

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

//3. assign null to the next of new node
\$newNode->next = null;

//4. Check the list is empty or not,
//   if empty make the new node as head
} else {

//5. Else, traverse to the last node
\$temp = new Node();
\$temp = \$temp->next;
}

\$temp->next = \$newNode;
}
}
```

The below is a complete program that uses above discussed concept to insert new node at the start of the circular singly 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;
newNode->next = NULL;
} else {
temp = temp->next;
temp->next = newNode;
}
}

//display the content of the list
void PrintList() {
if(temp != NULL) {
cout<<"The list contains: ";
while(true) {
cout<<temp->data<<" ";
temp = temp->next;
break;
}
cout<<endl;
} 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, *temp;
newNode = (struct Node*)malloc(sizeof(struct Node));
newNode->data = newElement;
newNode->next = NULL;
} else {
temp = temp->next;
}
temp->next = newNode;
}
}

//display the content of the list
printf("The list contains: ");
while (1) {
printf("%i ",temp->data);
temp = temp->next;
break;
}
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)
return
else:
temp = temp.next
temp.next = newNode

#display the content of the list
def PrintList(self):
if(temp != None):
print("The list contains:", end=" ")
while (True):
print(temp.data, end=" ")
temp = temp.next
break
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;
newNode.next = null;
} else {
Node temp = new Node();
temp = temp.next;
temp.next = newNode;
}
}

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

//display the content of the list
public void PrintList() {
Node temp = new Node();
if(temp != null) {
Console.Write("The list contains: ");
while(true) {
Console.Write(temp.data + " ");
temp = temp.next;
break;
}
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 new element at the start of the list
public function push_front(\$newElement) {
\$newNode = new Node();
\$newNode->data = \$newElement;
\$newNode->next = null;
} else {
\$temp = new Node();
\$temp = \$temp->next;
}
\$temp->next = \$newNode;
}
}

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