Singly Linked List operations

/*Program to impelement Singly Linked List operations
compiler- Turbo c++     author- Mangilal Sharma
--------------------------------------------------------*/
#include <process.h>
#include <conio.h>
#include <iostream.h>

class singly
{
 struct s_node
 {
  int data;
  s_node *link;
 }*p;
 public:
 void inslast(int);
 void insbeg(int);
 void insnext(int,int);
 void delelement(int);
 void delbeg();
 void dellast();
 void disp();
 int search(int);
 singly();
 ~singly();      //destructor that deallocate the memory adderess
};

void singly::inslast(int x)
{
 s_node *q,*t;
 if(p==NULL)
 {
  p=new s_node;
  p->data=x;
  p->link=NULL;
 }
 else
 {
  q=p;
  while(q->link!=NULL)
  q=q->link;
  t=new s_node;
  t->data=x;
  t->link=NULL;
  q->link=t;
 }
 cout<<" Inserted successfully at the end...\n";
 disp();
}

void singly:: insbeg(int x)
{
 s_node *q;
 q=p;
 p=new s_node;
 p->data=x;
 p->link=q;
 cout<<" Inserted successfully at the begining...\n";
 disp();
}

void singly::delelement(int x)
{
 s_node *q,*r;
 q=p;
 if(q->data==x)
 {
  p=q->link;
  delete q;
  return;
 }
 r=q;
 while(q!=NULL)
 {
  if(q->data==x)
  {
   r->link=q->link;
   delete q;
   return;
  }
  r=q;
  q=q->link;
 }
 cout<<" Element u entered   "<<x<<"  that  is not found..";
}

void singly:: delbeg()
{
 cout<<" The list before deletion:";
 disp();
 s_node *q;
 q=p;
 if(q==NULL)
 {
  cout<<" No data is present..";
  return;
 }
 p=q->link;
 delete q;
 return;
}

void singly:: dellast()
{
 cout<<" The list before deletion:";
 disp();
 s_node *q,*t;
 q=p;
 if(q==NULL)
 {
  cout<<" There is no data in the list...";
  return;
 }
 if(q->link==NULL)
 {
  p=q->link;
  delete q;
  return;
 }
 while(q->link->link!=NULL)
 q=q->link;
 q->link=NULL;
 return;
}

singly::~singly()
{
 s_node *q;
 if(p==NULL) return;
 while(p!=NULL)
 {
  q=p->link;
  delete p;
  p=q;
 }
}

void singly::disp()
{
 s_node *q;
 q=p;
 if(q==NULL)
 {
  cout<<" No data is in the list..";
  return;
 }
 cout<<" The items present in the list are :";
 while(q!=NULL)
 {
  cout<<" "<<q->data;
  q=q->link;
 }
}

void singly::insnext(int value,int position)
{
 s_node *temp,*temp1;
 temp=p;
 if(temp1==NULL)
 {
  temp1= new s_node;
  temp1->data=value;
  temp1->link=NULL;
  p=temp1;
  return;
 }
 for(int i=0;((i<position)&&(temp->link!=NULL)) ;i++)
 {
  if(i==(position-1))
  {
   temp1= new s_node;
   temp1->data= value;
   temp1->link=temp->link;
   temp->link=temp1;
  }
  temp=temp->link;
 }
 cout<<" Inserted successfully at the position...\n"<<position;
 disp();
}

int singly::search(int value)
{
 s_node *temp;
 temp=p;
 int position=0;
 while(temp!=NULL)
 {
  if(temp->data==value)
  return position+1;
  else
  {
   temp=temp->link;
   position=position+1;
  }
 }
 cout<<" Element "<<value<<" not found";
 return 0;
}

singly::singly()
{
 int v,p,ps,choice;
 p=NULL;
 while(1)
 {
  cout<<"\n\t\tOperations on  linked List..\n";
  cout<<"\t\t1. To Insert an Element in  linked list\n";
  cout<<"\t\t2. To Delete an Element from  linked list\n";
  cout<<"\t\t3. To Display the Elements of  linked list\n";
  cout<<"\t\t4. To Search an element\n";
  cout<<"\t\t5. To Main menu\n";
  cout<<"\t\t6. To Exit from Programme\n";
  cout<<"\n\t\t Enter Your Choice= ";
  cin>>choice;
  switch(choice)
  {
   case 1:
   cout<<"1.Insertion at begining\n2.Insertion at the end\n";
   cout<<"3.Insertion after the mentioned position\n";
   cout<<" Enter ur choice:";
   cin>>ps;
   cout<<" Enter the value to insert:";
   cin>>v;
   switch(ps)
   {
    case 1:insbeg(v);break;
    case 2:inslast(v);break;
    case 3:cout<<" Enter the position to insert the value:";
  cin>>p;
  insnext(v,p);break;
   default:cout<<" The choice is invalid";return;
   }break;

   case 2:
   cout<<"1.Delete the first element\n2.Delete the last element\n";
   cout<<"3.Enter the element to delete from the list\n";
   cout<<" Enter ur choice:";
   cin>>ps;
   switch(ps)
   {
    case 1:delbeg();
    cout<<" The list after deletion:";disp();break;
    case 2:dellast();
    cout<<" The list after deletion:";disp();break;
    case 3:disp();
    cout<<" Enter the element to delete:";
    cin>>v;
    delelement(v);
    cout<<" The list after deletion:";disp();break;
    default:
    cout<<" The option is invalid...";break;
   }break;
   case 3:
   disp();break;
   case 4:
   disp();
   cout<<" Enter the element to search:";
   cin>>v;
   cout<<" The position of the element "<< v<<"  is "<<search(v);
   getch();break;
   case 5:return;
   case 6:exit(1);
   default:cout<<" The option is invalid...";return;
  }
 }
}
/*=========================9Nov.,2010=============================*/