# C program to find the middle node of the singly linked list

Here, we are going to learn how to find the middle node of the singly linked list using C program?
Submitted by Nidhi, on August 23, 2021

Problem Solution:

Given a singly linked list, we have to find the middle node of the list.

Program:

The source code to find the middle node of the list is given below. The given program is compiled and executed using GCC compile on UBUNTU 18.04 OS successfully.

```// C program to find the middle node of

#include <stdio.h>
#include <stdlib.h>

//Self-referential structure to create the node.
typedef struct tmp {
int item;
struct tmp* next;
} Node;

//structure for creating the linked list.
typedef struct
{
Node* tail;

} List;

//Initialize List
void initList(List* lp)
{
lp->tail = NULL;
}

//Create node and return the reference of it.
Node* createNode(int item)
{
Node* nNode;

nNode = (Node*)malloc(sizeof(Node));

nNode->item = item;
nNode->next = NULL;

return nNode;
}

//Add a new item at the end of the list.
{
Node* node;
node = createNode(item);

//if list is empty.
lp->tail = node;
}
else {
lp->tail->next = node;
lp->tail = lp->tail->next;
}
}

//Add a new item at the beginning of the list.
{
Node* node;
node = createNode(item);

//if list is empty.
lp->tail = node;
}
else {
}
}

//To print the list from start to end of the list.
void printList(List* lp)
{
Node* node;

printf("\nEmpty List");
return;
}

while (node != NULL) {
printf("| %05d |", node->item);
node = node->next;

if (node != NULL)
printf("--->");
}
printf("\n\n");
}

void findMiddleNode(List* lp)
{
Node* temp;

int count = 0;
int middle = 0;

while (temp != NULL) {
count++;
temp = temp->next;
}

middle = count / 2;
if (count % 2 != 0)
middle += 1;
count = 0;

while (temp != NULL) {
count++;
if (count == middle) {
printf("Middle node is: %d\n", temp->item);
break;
}
temp = temp->next;
}
}

//Main function to execute program.
int main()
{
List* lp;

lp = (List*)malloc(sizeof(List));

initList(lp);

printf("List:\n");
printList(lp);

findMiddleNode(lp);

return 0;
}
```

Output:

```List:
| 00101 |--->| 00102 |--->| 00103 |--->| 00104 |--->| 00105 |

Middle node is: 103
```

Explanation:

Here, we created a self-referential structure to implement a linked list, a function to add a node at the start and end of the list, and a function findMiddleNode() to find the middle node from the linked list.

In the main() function, we created a singly linked list and called the function findMiddleNode() to find the middle node.

Preparation

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