Thursday, 12 May 2005

Graphs using c++

Graph

#include<iostream.h>
#include<conio.h>
class Queue
{
 private:
         int *a;//a can point to run time array
         int f,r,size;//f,r are subscripts, size is array size
 public:
Queue(int k=40);//40 is the default value to the constructor
~Queue();
  int isempty();
int isfull();
void insert(int);
int del();
int first();
int last();
void display();
};
Queue::Queue(int k)
{
 size=k;//value passed from the fun.call or default value k=40
//initial values
 f=0;
 r=-1;
 a=new int[size];//create an array &base adress is stored in obj
}
Queue::~Queue()
{
 delete[] a;//delete that array where a points
}
int Queue::isempty()
{
 return(r==-1);
}
int Queue::isfull()
{
 return(r==size-1);
}
void Queue::insert(int x)//x is value to be inserted
{
//testing for empty locations on right side of the Queue
 if(isfull())
 //or if(r==size-1)
   cout<<"insertion is not possible\n";
 else
 {
   r++;//move on next location
   a[r]=x;//insert x in array a at subscript 'r'
 }
}
int Queue::del()
{
 int x;
 if(isempty())//if q is empty retun(-1)
   return(-1);
 x=a[f];//copy 1st inserted value to x before it is deleted
 f++;//delete 1st inserted value(logically)
 if(f>r)//if q is empty after deletion,reinitialize f and r
 {
  f=0;
  r=-1;
 }
 return(x);//deleted value
}
void Queue::display()
{
 if(isempty())
cout<<"Queue is empty\n";
 else
 {
cout<<"Queue is as follows\n";
for(int i=f;i<=r;i++)//display a[i] where i values from f to r
cout<<a[i]<<"\t";
        cout<<"\n";
 }
}
int  Queue::first()
{
 if(isempty())//If Queue is empty return-1
   return(-1);
 else
   return(a[f]);//1st inserted value of the Queue
}
int Queue::last()
{
 if(isempty())//if Queue is empty return -1
   return(-1);
 else
   return(a[r]);//last inserted value of the Queue
}
void menu()
{
 cout<<"1.insertion\n";
 cout<<"2. deletion\n";
 cout<<"3. display Queue\n";
 cout<<"3.1st inserted value\n";
 cout<<"4.1st inserted value\n";
 cout<<"5.last inserted value\n";
 cout<<"6.exit\n";
}
/*void main()
{
 int ch,k,x;
 void menu();
 cout<<"enter size of the Queue\n";
 cin>>x;
 Queue Q(k);
 clrscr();
 menu();
 cout<<"enter ur choice\n";
 cin>>ch;
 while(ch<6)
 {
  switch(ch)
  {
    case 1:{
       cout<<"enter value to be inserted\n";
       cin>>x;
       if(x==-1)
cout<<"Invalid no\n";
       else
Q.insert(x);
       break;
       }//case
     case 2:{
x=Q.del();
if(x==-1)
  cout<<"Queue is empty,del is not possible\n";
else
  cout<<"deleted value="<<x<<"\n";
break;
} //case
     case 3:{
Q.display();
break;
} //case
    case 4:{
  x=Q.first();//function returns 1st inserted value
  if(x==-1)
   cout<<"Queue is empty\n";
  else
   cout<<"First insert value is"<<x<<"\n";
  break;
  }//case
    case 5:{
  x=Q.last();//function returns last inserted value
   if(x==-1)
    cout<<"Queue is empty\n";
else

  cout<<"last insert value is"<<x<<"\n";
break;

}//case
       }//switch
       menu();
       cout<<"enter ur choice\n";
       cin>>ch;
  }//while
} //main()*/


class Node
{
 private:
  int data;
  Node *link;
  friend class sll;
};
class sll
{
 private:
     Node *first;
 public:
     sll();
     ~sll();
     int isempty();
     void display();
     int length();
     void erase();
     void insert(int i, int x);
     int del(int i);
     int find(int i);
     Node *search(int x);
     sll(sll &a);//cc
     void create();
     void append(Node *k);
     void reverse();
 };
 sll::sll()
 {
  first=NULL;
 }
int sll::isempty()
{
 return(first==NULL);
}
void sll::display()
{
 Node *p;//p is a pointer to a //node
 if(isempty())
  cout<<"Linked list is empty\n";
 else
 {
  cout<<"Linked List is as follows\n";
  for(p=first;p!=NULL;p=p->link)
  cout<<p->data<<"\t"<<p->link<<"\n";
 }
}
int sll::length()
{
 Node *p;//p is a pointer to ode
 int ctr=0;
 p=first;
 while(p!=NULL)/*cnt each node in the linked list*/
 {
  ctr++;
  p=p->link;
 }//while
 return(ctr);

}
int sll::find(int i)
{
 Node *p;
 if(i<1||i>length())//i must be //b/w 1 and length
   return(-1);//ith node does //not exist
   p=first;
   for(int j=1;j<=i-1;j++)
    p=p->link;
   return(p->data);//ith node //data
 }
Node* sll::search(int x)
{
 Node *p=first;
 while(p!=NULL)
 {
   if(p->data==x)
    return(p);
   else
    p=p->link;
  }
  return(NULL);
}
/*k is a ptr to new node to be appended*/

void sll::append(Node *k)
{
 Node *last;//last is a ptr to //Node
 k->link=NULL;
 if(isempty())
  first=k;
 else
 {
  last=first;
  while(last->link!=NULL)
   last=last->link;
  last->link=k;/*attach last node and the new node k */
}
}
void sll::create()
{
  int x;
  Node *k;
  first=NULL;//initially Linked //list is empty
  cout<<"enter values terminated by -1 (or)!\n";
  cin>>x;
  while(x!=-1&&x!='!')
  {
   k=new Node;
   k->data=x;
   append(k);
   cin>>x;
  }
}
sll::sll(sll &a)
{
 Node *p,*k;
 first=NULL;
 p=a.first;
 while(p!=NULL)
 {
  k=new Node;
  k->data=p->data;
  append(k);
  p=p->link;
 }
}
void sll::erase()
{
 Node *p;
 while(!isempty())
 {
  p=first;
  first=first->link;
  delete p;
 }
}
sll::~sll()
{
 erase();
}
void sll::reverse()
{
 Node *cur,*prev,*next;
 next=first;
 cur=NULL;
 while(next!=NULL)
 {
  prev=cur;
  cur=next;
  next=next->link;
  cur->link=prev;
 }
 first=cur;
 }

void sll::insert(int i, int x)
{
 Node *p,*temp;
 if(i<0||i>length())
  cout<<"Non-existing Node\n";
 else
 {
  p=new Node;
  p->data=x;
  if(i==0)
  {
   p->link=first;
   first=p;
  }
  else
  {
   temp=first;
   for(int j=1;j<=i-1;j++)
    temp=temp->link;
   p->link=temp->link;
   temp->link=p;
  }
 }
}
int sll::del(int i)
{
 Node *p,*pres,*prev;
 int x;
 if(i<1||i>length())
  return(-1);
 else if(i==1)
 {
  p=first;
  first=first->link;
  x=p->data;
  delete p;
  return(x);
 }
 else
 {
  pres=first;
  for(int j=1;j<=i-1;j++)
  {
    prev=pres;
    pres=pres->link;
   }
   prev->link=pres->link;
   x=pres->data;
   delete pres;
   return(x);
  }
}
class graph
{
 private:
  int n;//no of vertices in the //graph
  sll *a;//a is ptr to array of object
 public:
  void create();
  int nov();
  int noe();
  int degree(int i);
  void bfs();
  void dfs();
  void traverse(int i,int *visited);
  ~graph();
  void display();
};
void graph::create()
{
 cout<<"enter no of vertices\n";
 cin>>n;
//create array of n objects, a is ptr to array, sll contructor is called n times
 a=new sll[n];
 for(int i=0;i<=n-1;i++)
 {
  cout<<"Enter adjacent vertex"<<i<<"in ascending terminated by -1\n";
  a[i].create();
 }
}
void graph::display()
{
 for(int i=0;i<=n-1;i++)
 {
  cout<<"Adj vertices of vertex"<<i<<":";
  a[i].display();
 }
}
/*void sll::display()
{
 Node *p;
 if(isempty())
  cout<<"No of Adj.vertices\n";
 else
 {
  for(p=first;p!=NULL;p=p->link)
   cout<<p->data<<"\t";
  cout<<"\n";
 }
} */
int graph::degree(int i)
{
 return(a[i].length());
}
void graph::bfs()
{
 Node *p;
 int i,*visited;
 Queue q;//constructor is called
visited=new int[n];
 for(i=0;i<=n-1;i++)//initially none of the vertices are visited
  visited[i]=false;//initially array with false
 for(i=0;i<=n-1;i++)//This is necessary in view of directed end disconnected graph
 {
  if(!visited[i])//if ith vertex is not visited,insert into the queue, i is starting //vertex
  {
   q.insert(i);
   do
   {
    j=q.del();//delete a vertex from the queue
    if(!visited[j])//jth vertex is not visited,display j
    {
     Node*p;
     cout<<j;
     visited[j]=true;//jth vertex is visited
//process adjacent vertices of jth vertex
     for(p=a[j].first;p!=NULL;p=p->link;)
     {
      //if the adjacent vertices is not visited, insert into the Queue
       if(!visited[p->data])
        q.insert(p->data);
     }//for
  }//if
 }
 while(!q.isempty());//execute loop untill queue is empty
 }//if
}//for
}function

void graph::dfs()
{
 int i,*visited;

 visited=new int[n];//create of size n;visited is a pointer to it
 for(i=0;i<=n-1;i++)//initially non of the vertices are visited
   visited[i]=false;//initially array with false,false,false
 for(i=0;i<=n-1;i++)//this is necessary in view of directed and disconnected graph
 {
  if(!visited[i])//if ith vertex is not visited,call the function on vertex i,
                 //where i is the starting vertex of componant
    traverse(i,visited);
 }
 }
void graph::traverse(int i,int *visited)
{
 Node *p;//p is a ptr to node
 if(!visited[i])//if ith vertex is not visited,visit it now
 {
  cout<<i;
  visited[i]=true;//mark the ith vertex as visited vertex
//process ith adjacent vertices of ith vertex
  for(p=a[i].fist;p!=NULL;p=p->link)
  {
   if(!visited[p->data])//if adjacent vertex is not visited,
                        //call the same function on adjacent vertex
       traverse(p->data,visited);
  }
 }
}
void menu()
{
 cout<<"1.Display the graph\n";
 cout<<"2.No of vertices &edges of graph\n";
 cout<<"3.Degree of each vertex in the graph\n";
 cout<<"4.Bread First Search \n";
 cout<<"5.Dfs\n";
 cout<<"6.exit\n";
}
void main()
{
 graph g;//vertices
 int ch;
 g.create();//create a graph whose address is stored in object g
 clrscr();
 menu();
 count<<"enter your choice\n";
 cin>>ch;
 while(ch<6)
 {
  switch(ch)
  {
   case 1:{
     g.display();
     break;
          }//case
   case 2:{
 //nov() returns no of vertices and edges
      cout<<"No of vertices are="<<g.nov()<<"\n";
      cout<<"No. edges="<<g.noe()<<"\n";
      break;
           }//case 2
   case 3:
          {
        //i is the vertex no, degree of i is the degree of i is the
 //degree of ith vertex, where i varies from  0 to no.of (vertices-1) 
       cout<<i<<"\t"<<g.degree(i)<<"\n";
       break;
        }
   case 4:
         {
         g.bfs();//visit the graph in bfs
         cout<<"\n";
         break;
         }
   case 5:
         {
          g.dfs();//visit the graph in dfs
         cout<<"\n";
         break;
         }

  } //switch
menu();
cout<<"enter your choice\n";
cin>>ch;
}//while
getch();
}//main()


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