Singly_LinkedList

#include<stdio.h>
#include<stdlib.h>
void insertbeg(int);
void insertend(int);
void insertmid(int);
void display();
void deletefront();
void deleteend();



struct node
{
int data;
struct node*ptr;
};

struct node *start;
struct node*temp;

int main()
{
    int op,n;
   do{

    printf("\n choose \n 1.insert@beg \n 2.insert@end \n 3.insert@mid \n 4.delete@beg \n 5.delete@end \n 6.delete@mid \n 7.exit \n");
    scanf("%d",&op);
    switch(op)
    {
    case 1:
        printf("enter the value : \t");
        scanf("%d",&n);
        insertbeg(n);
        display();
        break;

    case 2:
        printf("enter the value : \t");
        scanf("%d",&n);
        insertend(n);
        display();
        break;

    case 3:
        printf("enter the value: \t");
        scanf("%d",&n);
        insertmid(n);
        display();
        break;
    case 4:
        deletefront();
        display();
        break;
    case 5:
        deleteend();
        display();
        break;
    case 6:
        deletemid();
        display();
        break;
    case 7:
        return 0;
        break;

    }
}while(op!=7);
}

void insertbeg(int n)
{
  temp=(struct node*)malloc(sizeof(struct node*));
  if(start==NULL)
  {
      temp->ptr=NULL;
      temp->data=n;
      start=temp;
  }else
  {
      temp->ptr=start;
      temp->data=n;
      start=temp;
  }
}

void display()
{
    if(start==NULL)
    {

        printf("it is empty");
    }else{
    printf("list : \t");
    for(temp=start;temp!=NULL;temp=temp->ptr)
    {
        printf("%d \t",temp->data);
    }
    }
}

void insertend(int n)
{
    struct node*p;
    temp=(struct node*)malloc(sizeof (struct node*));
    if(start==NULL)
    {
        temp->ptr=NULL;
        temp->data=n;
        start=temp;

    }else
    {
        p=start;
       while(p->ptr!=NULL)
       {
           p=p->ptr;
       }
       p->ptr=temp;
       temp->ptr=NULL;
       temp->data=n;

    }
}

void insertmid(int n)
{
    int pos;
    struct node*p;
    temp=(struct node*)malloc(sizeof (struct node *));
    printf("enter the position : \t");
    scanf("%d",&pos);
    p=start;
    for(int i=1;i<pos-1;i++)
    {
        p=p->ptr;
    }
    temp->ptr=p->ptr;
    p->ptr=temp;
    temp->data=n;
}

void deletefront()
{
    temp=(struct node*)malloc(sizeof(struct node *));
    if(start==NULL)
    {
        printf("it is empty");
    }
    else if(start->ptr==NULL)
    {
        temp=start;
        start=NULL;
        printf("deleted element is %d ",temp->data);
        free(temp);
    }else
    {

        temp=start;
        start=start->ptr;
        printf("deleted element is %d ",temp->data);
        free(temp);
    }
}

void deleteend()
{
    struct node*t;
    temp=(struct node*)malloc(sizeof(struct node*));
    if(start==NULL)
    {
        printf("it is empty");
    }else if(start->ptr==NULL)
    {
        temp=start;
        start=NULL;
        printf("deleted element is %d ",temp->data);
        free(temp);

    }else{
      temp=start;
      t=start->ptr;
      while(t->ptr!=NULL)
      {
          t=t->ptr;
          temp=temp->ptr;
      }
      temp->ptr=NULL;
      printf("deleted element is %d ",t->data);
      free(t);
     }

}

void deletemid()
{
    struct node*t;
    struct node*p;
    if(start==NULL)
    {
        printf("empty!!");
    }
    else{
        printf("enter the position : \t");
        int pos;
        scanf("%d",&pos);
        if(pos==1 & &start->ptr==NULL)
        {
            temp=start;
            start=NULL;
            printf("deleted element is %d ",temp->data);
            free(temp);
        }
        else if(pos==1)
        {
            temp=start;
            start=start->ptr;
            printf("deleted element is %d ",temp->data);
            free(temp);
        }else
        {
            temp=start;
            for(int i=1;i<pos-1;i++)
            {
                temp=temp->ptr;
            }
            t=temp->ptr;
            temp->ptr=t->ptr;
            printf("deleted element is %d ",t->data);
            free(t);
        }
    }
}