C Program to Add Corresponding Positioned Elements of Two Linked Lists

This C Program adds the corresponding positioned elements of 2 linked lists and display.

Here is source code of the C Program to add corresponding positioned elements of 2 linked lists. The C program is successfully compiled and run on a Linux system. The program output is also shown below.

```
/*
```

 * C Program to Add Corresponding Positioned Elements of 2 Linked Lists

```
 */
```
```
#include <stdio.h>
```
```
#include <stdlib.h>
```
```
#include <ctype.h>
```
```
 
```
```
struct node
```
```
{
```
```
    int num;
```
```
    struct node *next;
```
```
};
```
```
 
```
```
int feednumber(struct node **);
```

struct node *addlist(struct node *, struct node *, int, int);

```
void release(struct node **);
```
```
void display(struct node *);
```
```
 
```
```
int main()
```
```
{
```
```
    struct node *p = NULL;
```
```
    struct node *q = NULL;
```
```
    struct node *res = NULL;
```
```
    int pcount = 0, qcount = 0;
```
```
 
```
```
    printf("Enter first number\n");
```
```
    pcount = feednumber(&p);
```
```
    printf("Enter second number\n");
```
```
    qcount = feednumber(&q);
```
```
    printf("Displaying list1: ");
```
```
    display(p);
```
```
    printf("Displaying list2: ");
```
```
    display(q);
```

    res = addlist(p, q, pcount, qcount);

    printf("Displaying the resulting list: ");

```
    display(res);
```
```
    release(&p);
```
```
    release(&q);
```
```
    release(&res);
```
```
 
```
```
    return 0;
```
```
}
```
```
 
```
```
/*Function to create nodes of numbers*/
```
```
int feednumber(struct node **head)
```
```
{
```
```
    char ch, dig;
```
```
    int count = 0;
```
```
    struct node *temp, *rear = NULL;
```
```
 
```
```
    ch = getchar();
```
```
    while (ch != '\n')
```
```
    {
```
```
        dig = atoi(&ch);
```

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

```
        temp->num = dig;
```
```
        temp->next = NULL;
```
```
        count++;
```
```
        if ((*head) == NULL)
```
```
        {
```
```
            *head = temp;
```
```
            rear = temp;
```
```
        }
```
```
        else
```
```
        {
```
```
            rear->next = temp;
```
```
            rear = rear->next;
```
```
        }
```
```
        ch = getchar();
```
```
    }
```
```
 
```
```
    return count;
```
```
}
```
```
 
```

/*Function to display the list of numbers*/

```
void display (struct node *head)
```
```
{
```
```
    while (head != NULL)
```
```
    {
```
```
        printf("%d", head->num);
```
```
        head = head->next;
```
```
    }
```
```
    printf("\n");
```
```
}
```
```
 
```

/*Function to free the allocated list of numbers*/

```
void release (struct node **head)
```
```
{
```
```
    struct node *temp = *head;
```
```
 
```
```
    while ((*head) != NULL)
```
```
    {
```
```
        (*head) = (*head)->next;
```
```
        free(temp);
```
```
        temp = *head;
```
```
    }
```
```
}
```
```
 
```

/*Function to add the list of numbers and store them in 3rd list*/

struct node *addlist(struct node *p, struct node *q, int pcount, int qcount)

```
{
```

    struct node *ptemp, *qtemp, *result = NULL, *temp;

```
    int i, carry = 0;
```
```
 
```
```
    while (pcount != 0 && qcount != 0)
```
```
    {
```
```
        ptemp = p;
```
```
        qtemp = q;
```

        for (i = 0; i < pcount - 1; i++)

```
        {
```
```
            ptemp = ptemp->next;
```
```
        }
```

        for (i = 0; i < qcount - 1; i++)

```
        {
```
```
            qtemp = qtemp->next;
```
```
        }
```

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

        temp->num = ptemp->num + qtemp->num + carry;

```
        carry = temp->num / 10;
```
```
        temp->num = temp->num % 10;
```
```
        temp->next = result;
```
```
        result = temp;
```
```
        pcount--;
```
```
        qcount--;
```
```
    }
```

    /*both or one of the 2 lists have been read completely by now*/

```
    while (pcount != 0)
```
```
    {
```
```
        ptemp = p;
```

        for (i = 0; i < pcount - 1; i++)

```
        {
```
```
            ptemp = ptemp->next;
```
```
        }
```

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

```
        temp->num = ptemp->num + carry;
```
```
        carry = temp->num / 10;
```
```
        temp->num = temp->num % 10;
```
```
        temp->next = result;
```
```
        result = temp;
```
```
        pcount--;
```
```
    }
```
```
    while (qcount != 0)
```
```
    {
```
```
        qtemp = q;
```

        for (i = 0; i < qcount - 1; i++)

```
        {
```
```
            qtemp = qtemp->next;
```
```
        }
```

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

```
        temp->num = qtemp->num + carry;
```
```
        carry = temp->num / 10;
```
```
        temp->num = temp->num % 10;
```
```
        temp->next = result;
```
```
        result = temp;
```
```
        qcount--;
```
```
    }
```
```
 
```
```
    return result;
```
```
}
```

$ cc add2lists.c
$ ./a.out
Enter first number
12345
Enter second number
5678903
Displaying list1: 12345
Displaying list2: 5678903
Displaying the resulting list: 5691248

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