Program for graph coloring using greedy approach

#include<iostream>
#include<list>
using namespace std;

class Graph
{
 int V,E;
 int **adj;
 list<int> *str;
 public:
  Graph()
  {
      cout<<"Enter the no of vertices and edges:"<<endl;
      cin>>V>>E;
      adj=new int*[V];
      for(int i=0;i<V;i++)
      adj[i]=new int[V];
      
      str=new list<int>[V];
      
      int v1,v2;
      for(int i=0;i<E;i++)
      {
       cout<<endl<<"Enter vertices for edge :"<<i+1;
       cin>>v1>>v2;
       
           adj[v1-1][v2-1]=1;
           adj[v2-1][v1-1]=1;
      }
  }
  ~Graph()
  {
   for(int i=0;i<V;i++)
   delete []adj[i];
   delete []adj;
  }
  
  void graphColoring();
};

void Graph::graphColoring()
{
 int result[V];
 int available[V];
 
 result[0]=0;  //assign color 0 to vertex-0
 str[0].push_back(0);
 
 for(int i=1;i<V;i++)
 result[i]=-1;
 
 for(int i=0;i<V;i++)    // Color is available
 available[i]=0;
 
 for(int u=1;u<V;u++)
 {
  for(int i=0;i<V;i++)
  {
   if(adj[u][i]==1)
      if(result[i]!=-1)
      available[result[i]]=1;
     }
     
  int clr;
  for(clr=0;clr<V;clr++)
  if(available[clr]==0)
  break;
  
  result[u]=clr;
  str[clr].push_back(u);
  
   for(int i=0;i<V;i++)
   {
    if(adj[u][i]==1)
       if(result[i]!=-1)
       available[result[i]]=0;
      }
    //  cout<<result[u];
  
 }
 
 for(int i=0;i<V;i++)
 {
  cout<<"Vertex :"<<i+1<<" Color: "<<result[i]<<endl;
 }
 cout<<endl<<endl;
 list<int>::iterator j;
 int i;
 for(i=0;i<V&&str[i].begin()!=str[i].end();i++)
 {
  cout<<"Color :"<<i<< "  Vertex ";
  for(j=str[i].begin();j!=str[i].end();++j)
  cout<<" "<<(*j)+1;
  cout<<endl;
 }
 
}

int main()
{
 Graph g;
 g.graphColoring();
 
 return 0;
}