singly linked list.c

//a C program to implement single linked list functions(insertion, deletion, display)

#include<stdio.h>
#include<stdlib.h>
struct node
{
int data;
struct node *next;
};
struct node *head=NULL, *ptr;

void insert_begin(int value)
{
struct node *temp;
temp=(struct node *)malloc(sizeof(struct node));
temp->data=value;
temp->next=NULL;
if (head==NULL)
{
head=temp;
}
else
{
temp->next=head;
head=temp;
}
}

void insert_end(int value)
{
struct node *temp;
temp=(struct node *)malloc(sizeof(struct node));
temp->data=value;

if (head==NULL)
{
head=temp;
}
else
{
ptr=head;
while(ptr->next !=NULL)
{
ptr=ptr->next;
}
ptr->next=temp;
temp->next=NULL;
}
}

void insert_after_specified_ele(int value,int ele)
{
struct node *temp;
temp=(struct node *)malloc(sizeof(struct node));
temp->data=value;
if (head==NULL)
{
head=temp;
}
else
{
ptr=head;
while(ptr->data != ele)
{
ptr=ptr->next;
}
temp->next=ptr->next;
ptr->next=temp;
}
}

void delete_begin()
{
if(head==NULL)
{
printf("Empty list!");
}
else
{
ptr=head;
head=head->next;
ptr->next=NULL;
free(ptr);
}
}

void delete_end()
{
if(head==NULL)
{
printf("Empty list!");
}
else
{
struct node *p;
ptr=head;
while(ptr->next !=NULL)
{
p=ptr;
ptr=ptr->next;
}
p->next=NULL;
free(ptr);
}
}

void delete_middle(int ele)
{
if(head==NULL)
{
printf("List is Empty!");
}
else
{
struct node* p;
ptr=head;
while(ptr->data != ele)
{
p=ptr;
ptr=ptr->next;
}
p->next=ptr->next;
free(ptr);
}
}

void display()
{
if(head==NULL)
{
printf("List is empty!");
}
else
{
ptr=head;
while(ptr !=NULL)
{
printf("%d ",ptr->data);
ptr=ptr->next;
}
printf("\n");
}
}

void main()
{
int value, ele, ch;
printf("\n 1. Insert at beginning \n 2. Insert at end \n 3. Insert after specified value \n 4.Delete at beginning \n 5. Delete at end\n 6. Delete in middle\n 7. Exit\n \n");


while(1)
{
printf("Enter your choice\n");
scanf("%d",&ch);
switch(ch)
{
case 1:
{
printf("Enter the desired value");
scanf("%d",&value);
insert_begin(value);
display();
break;
}
case 2:
{
printf("Enter the desired value");
scanf("%d",&value);
insert_end(value);
display();
break;
}
case 3:
{
printf("Enter the desired value");
scanf("%d",&value);
printf("Enter the specified element after which to insert:");
scanf("%d",&ele);
insert_after_specified_ele(value,ele);
display();
break;
}
case 4:
{
delete_begin();
display();
break;
}
case 5:
{
delete_end;
display();
break;
}
case 6:
{
printf("Enter the element that is to be deleted");
scanf("%d",&ele);
delete_middle(ele);
display();
break;
}
case 7:
{
exit(0);
}
}
}
}