A program to Delete a node in a Link List.

#include<iostream.h>
#include<conio.h>

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

node *start=NULL,*x,*y,*z;

void create()
{
if(start==NULL)
{
start=new node;
cout<<"\nEnter data: ";
cin>>start->data;
start->link=NULL;
x=start;
}
else
{
y=new node;
cout<<"\nEnter data: ";
cin>>y->data;
y->link=NULL;
x->link=y;
x=y;
}
}

void begin()
{
if(start==NULL)
cout<<"\nNo data present.\n";
else
{
z=start;
start=start->link;
z->link=NULL;
delete z;
}
}

void end() // ERROR: cannot create after deletion at end.
{
if(start==NULL)
cout<<"\nNo data present.\n"<<endl;
else
{
z=start;
y=z->link;
while(y->link!=NULL)
{
z=z->link;
y=y->link;
}
z->link=NULL;
delete y;
}
}

void mid()
{
int val;

if(start==NULL)
cout<<"\nNo Data present.\n";
else
{
cout<<"\nEnter value which is to be deleted: ";
cin>>val;
z=start;
y=z->link;
if(z->data==val)
{
start=start->link;
z->link=NULL;
delete z;
}
else
{
while(y!=NULL && y->data!=val)
{
y=y->link;
z=z->link;
}
if(y->data==val)
{
z->link=y->link;
y->link=NULL;
delete y;
}
}
}
}

void display()
{
z=start;
cout<<"\nLink list as follows: ";
while(z!=NULL)
{
cout<<z->data<<" ";
z=z->link;
}
cout<<"\n\n";
}

void main()
{
 clrscr();

 int ch;

 do 
  {
   cout<<"1. Create a Link List."<<endl;
   cout<<"2. Delete at begining."<<endl;
   cout<<"3. Delete at end."<<endl;
   cout<<"4. Delete in the middle."<<endl;
   cout<<"5. Display Link List."<<endl;
   cout<<"6. Exit."<<endl;
   cout<<"Enter your choice: ";
   cin>>ch;

   switch(ch)
    {
     case 1: {
                 create();
                 break;
                }
     case 2: {
                 begin();
                 break;
                }
     case 3: {
                 end();
                 break;
                }
     case 4: {
                 mid();
                 break;
                }
     case 5: {
                 display();
                 break;
                }
     case 6: {
                 break;
                }
     default:{
                 cout<<"\nWrong choice entered.\n";
                }
    }
   cout<<endl;
  }
 while(ch!=6);
}

< Back