Singly Linked List in C Programming

#include
#include
#define NULL 0
void main()
{
struct node{
 int data;
 struct node *link;
};
typedef struct node node;
int val,ch,ch2,cnt,loc,flag=0,num;
node *first=NULL,*temp,*ptr,*prv,*next;
char c='y';
clrscr();
 while(c=='y')
 {
  printf("\n1.Insert \n2.Delete \n3.Display \n4.Search \n5.Exit");
  printf("\n Enter your choice:");
  scanf("%d",&ch);

  switch(ch)
  {
   case 1:
    printf("\n1.Insert beginning \n2.Insert End \n3.Insert before given node\n4.insret after given node");
    printf("\nEnter your choice:");
    scanf("%d",&ch2);

    printf("\n Enter value:");
    scanf("%d",&val);




    switch(ch2)
    {


    case 1:
     temp=(node*)malloc(sizeof(node));
     temp->data=val;
     if(first==NULL)
     temp->link=NULL;

     temp->link=first;
     first=temp;
     break;
    case 2:
     temp=(node*)malloc(sizeof(node));
     temp->data=val;
     temp->link=NULL;
     ptr=first;

     if(first==NULL)
      first=temp;
     else
     {
      while(ptr->link!=NULL)
      {
       ptr=ptr->link;
      }
     }
     ptr->link=temp;
     break;
    case 3:
     temp=(node*)malloc(sizeof(node));
     temp->data=val;


     printf("\n Enter node before you want to add node:");
     scanf("%d",&num);
     ptr=first;

     while(ptr->data!=num)
     {
      prv=ptr;
      ptr=ptr->link;

     }
     temp->link=ptr;

     if(ptr==first)
      first=temp;
     else
      prv->link=temp;

     break;
    case 4:
     temp=(node*)malloc(sizeof(node));
     temp->data=val;
     temp->link=NULL;

     printf("\n Enter node after you want to add node:");
     scanf("%d",&num);
     ptr=first;
     while(ptr->data!=num)
     {
      ptr=ptr->link;
     }
     temp->link=ptr->link;
     ptr->link=temp;
     break;
    }
    break;
   case 2:
    printf("\n1.Delete beginning \n2.Delete End \n3.Delete by Element");
    printf("\nEnter your choice:");
    scanf("%d",&ch2);
    


switch(ch2)
    {
     case 1:
      if(first==NULL)
       printf("\n List is empty.");
      else
      {
       temp=first;
       printf("\n Deleted element is:%d",temp->data);
       first=first->link;
      }
      break;
     case 2:
      if(first==NULL)
       printf("\n List is empty.");
      else
      {
       temp=first;
       ptr=temp;
       while(temp->link!=NULL)
       {
        ptr=temp;
        temp=temp->link;
       }
       printf("\n Deleted element is:%d",temp->data);
       ptr->link=NULL;
       if(first==ptr)
       first=NULL;
      }
      break;
     case 3:
      if(first==NULL)
       printf("\n List is empty.");
      else
      {
       temp=first;

       printf("\n Enter element you want to delete:");
       scanf("%d",&num);
       if(temp->link!=NULL && temp->data==num)
       {
        first=temp->link;
        free(temp);
       }
       else if(temp->link==NULL && temp->data==num)
       {
        first=NULL;
        free(temp);
       }
       else
       {
        ptr=first;
        while(ptr->data!=num)
        {
         prv=ptr;
         ptr=ptr->link;
        }
       }
       temp=ptr;
       prv->link=ptr->link;
       free(temp);
      }
      break;
    }
    break;
   case 3:
    if(first==NULL)
    printf("\n List is empty.");
    else
    {
     temp=first;
     while(temp!=NULL)
     {
      printf("\t %d",temp->data);
      temp=temp->link;
     }
    }
    break;
   case 4:
    if(first==NULL)
    printf("\n Linked List is empty");
    else
    {
     printf("\n Enter element you want to search:");
     scanf("%d",&val);
     ptr=first;
     flag=0;
     while(ptr!=NULL)
     {

      if(ptr->data==val)
      {
       flag=1;
       break;
      }
      else
       flag=0;
      ptr=ptr->link;
     }
     if(flag==1)
      printf("\n Element found linked list.");
     else
      printf("\n Element is not found in linked list");
    }
    break;
   case 5:
    exit(0);
  }
 }
}

OUTPUT

1.Insert
2.Delete
3.Display
4.Search
5.Exit
 Enter your choice:1

1.Insert beginning
2.Insert End
3.Insert before given node
4.insret after given node
Enter your choice:1

 Enter value:22

1.Insert
2.Delete
3.Display
4.Search
5.Exit
 Enter your choice:1

1.Insert beginning
2.Insert End
3.Insert before given node
4.insret after given node
Enter your choice:2

 Enter value:44

1.Insert
2.Delete
3.Display
4.Search
5.Exit
 Enter your choice:1

1.Insert beginning
2.Insert End
3.Insert before given node
4.insret after given node
Enter your choice:3


 Enter value:11

 Enter node before you want to add node:22

1.Insert
2.Delete
3.Display
4.Search
5.Exit
 Enter your choice:1

1.Insert beginning
2.Insert End
3.Insert before given node
4.insret after given node
Enter your choice:4

 Enter value:33

 Enter node after you want to add node:22

1.Insert
2.Delete
3.Display
4.Search
5.Exit
 Enter your choice:3
                  11      22      33      44
1.Insert
2.Delete
3.Display
4.Search
5.Exit
 Enter your choice:4

 Enter element you want to search:33

 Element found linked list.
1.Insert
2.Delete
3.Display
4.Search
5.Exit
 Enter your choice:2

1.Delete beginning
2.Delete End
3.Delete by Element
Enter your choice:1

 Deleted element is:11
1.Insert
2.Delete
3.Display
4.Search
5.Exit
 Enter your choice:2

1.Delete beginning
2.Delete End
3.Delete by Element
Enter your choice:2

 Deleted element is:44
1.Insert
2.Delete
3.Display
4.Search
5.Exit
 Enter your choice:3
         22      33
1.Insert
2.Delete
3.Display
4.Search
5.Exit
 Enter your choice:2

1.Delete beginning
2.Delete End
3.Delete by Element
Enter your choice:3

 Enter element you want to delete:22

1.Insert
2.Delete
3.Display
4.Search
5.Exit
 Enter your choice:3
         33
1.Insert
2.Delete
3.Display
4.Search
5.Exit
 Enter your choice:2

1.Delete beginning
2.Delete End
3.Delete by Element
Enter your choice:3

 Enter element you want to delete:33

1.Insert
2.Delete
3.Display
4.Search
5.Exit
 Enter your choice:4

 Linked List is empty