Singly Linked List in C

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Here you will learn about singly linked list in C.

What is Singly Linked List (SLL)?

The simplest kind of linked list is a singly liked list (SLL) which has one link per node. It has two parts, one part contains data and other contains address of next node. The structure of a node in a SLL is given as in C:
struct node
{
    int data;
    struct node *next;
};

 

Also Read: Circular Linked List in C

 

The program is given below that will perform insertion, deletion and display a singly linked list.

Singly Linked List in C

#include<stdio.h>
#include<conio.h>
#include<process.h>

struct node
{
    int data;
    struct node *next;
}*start=NULL,*q,*t;

int main()
{
    int ch;
    void insert_beg();
    void insert_end();
    int insert_pos();
    void display();
    void delete_beg();
    void delete_end();
    int delete_pos();

    while(1)
    {
        printf("\n\n---- Singly Linked List(SLL) Menu ----");
        printf("\n1.Insert\n2.Display\n3.Delete\n4.Exit\n\n");
        printf("Enter your choice(1-4):");
        scanf("%d",&ch);

        switch(ch)
        {
            case 1:
                    printf("\n---- Insert Menu ----");
                    printf("\n1.Insert at beginning\n2.Insert at end\n3.Insert at specified position\n4.Exit");
                    printf("\n\nEnter your choice(1-4):");
                    scanf("%d",&ch);

                    switch(ch)
                    {
                        case 1: insert_beg();
                                break;
                        case 2: insert_end();
                                break;
                        case 3: insert_pos();
                                break;
                        case 4: exit(0);
                        default: printf("Wrong Choice!!");
                    }
                    break;

            case 2: display();
                    break;

            case 3: printf("\n---- Delete Menu ----");
                    printf("\n1.Delete from beginning\n2.Delete from end\n3.Delete from specified position\n4.Exit");
                    printf("\n\nEnter your choice(1-4):");
                    scanf("%d",&ch);

                    switch(ch)
                    {
                        case 1: delete_beg();
                                break;
                        case 2: delete_end();
                                break;
                        case 3: delete_pos();
                                break;
                        case 4: exit(0);
                        default: printf("Wrong Choice!!");
                    }
                    break;
            case 4: exit(0);
                    default: printf("Wrong Choice!!");
        }
    }
    return 0;
}

void insert_beg()
{
    int num;
    t=(struct node*)malloc(sizeof(struct node));
    printf("Enter data:");
    scanf("%d",&num);
    t->data=num;

    if(start==NULL)        //If list is empty
    {
        t->next=NULL;
        start=t;
    }
    else
    {
        t->next=start;
        start=t;
    }
}

void insert_end()
{
    int num;
    t=(struct node*)malloc(sizeof(struct node));
    printf("Enter data:");
    scanf("%d",&num);
    t->data=num;
    t->next=NULL;

    if(start==NULL)        //If list is empty
    {
        start=t;
    }
    else
    {
        q=start;
        while(q->next!=NULL)
        q=q->next;
        q->next=t;
    }
}

int insert_pos()
{
    int pos,i,num;
    if(start==NULL)
    {
        printf("List is empty!!");
        return 0;
    }

    t=(struct node*)malloc(sizeof(struct node));
    printf("Enter data:");
    scanf("%d",&num);
    printf("Enter position to insert:");
    scanf("%d",&pos);
    t->data=num;

    q=start;
    for(i=1;i<pos-1;i++)
    {
        if(q->next==NULL)
        {
            printf("There are less elements!!");
            return 0;
        }

        q=q->next;
    }

    t->next=q->next;
    q->next=t;
    return 0;
}

void display()
{
    if(start==NULL)
    {
        printf("List is empty!!");
    }
    else
    {
        q=start;
        printf("The linked list is:\n");
        while(q!=NULL)
        {
            printf("%d->",q->data);
            q=q->next;
        }
    }
}

void delete_beg()
{
    if(start==NULL)
    {
        printf("The list is empty!!");
    }
    else
    {
        q=start;
        start=start->next;
        printf("Deleted element is %d",q->data);
        free(q);
    }
}

void delete_end()
{
    if(start==NULL)
    {
        printf("The list is empty!!");
    }
    else
    {
        q=start;
        while(q->next->next!=NULL)
        q=q->next;

        t=q->next;
        q->next=NULL;
        printf("Deleted element is %d",t->data);
        free(t);
    }
}

int delete_pos()
{
    int pos,i;

    if(start==NULL)
    {
        printf("List is empty!!");
        return 0;
    }

    printf("Enter position to delete:");
    scanf("%d",&pos);

    q=start;
    for(i=1;i<pos-1;i++)
    {
        if(q->next==NULL)
        {
            printf("There are less elements!!");
            return 0;
        }
        q=q->next;
    }

    t=q->next;
    q->next=t->next;
    printf("Deleted element is %d",t->data);
    free(t);

    return 0;
}

 

Output
—- Singly Linked List(SLL) Menu —-
1.Insert
2.Display
3.Delete
4.ExitEnter your choice(1-4):1—- Insert Menu —-
1.Insert at beginning
2.Insert at end
3.Insert at specified position
4.ExitEnter your choice(1-4):1
Enter data:4—- Singly Linked List(SLL) Menu —-
1.Insert
2.Display
3.Delete
4.ExitEnter your choice(1-4):2
The linked list is:
4->

—- Singly Linked List(SLL) Menu —-
1.Insert
2.Display
3.Delete
4.Exit

Enter your choice(1-4):4

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22 thoughts on “Singly Linked List in C”

  3. divya goel

    whoa !!.. awesome program but it's countering a problem while displaying the list it says list is empty though i've inserted numbers in the beginning and end both then i inserted at desired position n then chose option 4 i.e display it saying that list is empty and then it says press any key to continue i've done accordingly but it repeatedly says press any key to cont. … agn n agn so problem is in d code of display please can ya wrk on it ??…

    Reply
  13. Ishika Mitra

    the program is not working …so many errors are there . please do it properly before putting it on website. you just wasted my time.

    Reply
  14. shreyas

    Delete end will not work for linked list with single element.
    q->next->next can generate errors if q->next is NULL.
    You can change by using an additional pointer.

    Reply
  16. Arnob Banik

    If you try to delete the first element in with the list containing only one element, it gives an error. Please fix it.

    Reply
  17. TANU

    Write a program driven program to implement following operations on the single linked list .
    (a) Insert a node at the front of the linked list.
    (b) Insert a node at the end of the linked list.
    (C) Insert a node at the given position in the link list.

    Reply

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