C Program to Find Middle Element of a Linked List

This C Program prints the middle most node of a linked list.

Here is source code of the C Program print the middle most node of a linked list. The C program is successfully compiled and run on a Linux system. The program output is also shown below.

```
/*
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 * C Program to Print Middle most Node of a Linked List

```
 */ 
```
```
#include <stdio.h>
```
```
#include <stdlib.h>
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```
 
```
```
struct node
```
```
{
```
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    int num;
```
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    struct node *next;
```
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};
```
```
 
```
```
void create(struct node **);
```
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void middlenode(struct node *);
```
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void release(struct node **);
```
```
 
```
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int main()
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```
{
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```
    struct node *p = NULL;
```
```
 
```

    printf("Enter data into the list\n");

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    create(&p);
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    middlenode(p);
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    release (&p);
```
```
 
```
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    return 0;
```
```
}
```
```
 
```
```
void middlenode(struct node *head)
```
```
{
```
```
    struct node *p, *q;
```
```
    int flag = 0;
```
```
 
```
```
    q = p = head;
```

    /*for every two hops of q, one hop for p*/

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    while (q->next != NULL)
```
```
    {
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```
        q = q->next;
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        if (flag)
```
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        {
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            p = p->next;
```
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        }
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        flag = !flag;
```
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    }
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```
    if (flag)
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```
    {
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        printf("List contains even number of nodes\nThe middle two node's values are: %d  %d\n", p->next->num, p->num);

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    }
```
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    else
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```
    {
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        printf("The middle node of the list is: %d\n", p->num);

```
    }
```
```
}
```
```
 
```
```
void create(struct node **head)
```
```
{
```
```
    int c, ch;
```
```
    struct node *temp;
```
```
 
```
```
    do
```
```
    {
```
```
        printf("Enter number: ");
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        scanf("%d", &c);
```

        temp = (struct node *)malloc(sizeof(struct node));

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        temp->num = c;
```
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        temp->next = *head;
```
```
        *head = temp;
```

        printf("Do you wish to continue [1/0]: ");

```
        scanf("%d", &ch);
```
```
    } while (ch != 0);
```
```
    printf("\n");
```
```
}
```
```
 
```
```
void release(struct node **head)
```
```
{
```
```
    struct node *temp = *head;
```
```
    *head = (*head)->next;
```
```
    while ((*head) != NULL)
```
```
    {
```
```
        free(temp);
```
```
        temp = *head;
```
```
        (*head) = (*head)->next;
```
```
    }
```
```
}
```

$ cc middlenode.c 
$ ./a.out
Enter data into the list
Enter number: 1
Do you wish to continue [1/0]: 1
Enter number: 2
Do you wish to continue [1/0]: 1
Enter number: 3
Do you wish to continue [1/0]: 1
Enter number: 4
Do you wish to continue [1/0]: 1
Enter number: 5
Do you wish to continue [1/0]: 0
 
The middle node of the list is: 3

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