topologicaldfs.cpp

#include<iostream.h>]
#include<stdio.h>
#include<stdlib.h>
#include<conio.h>
int count,comp, e[10][10],n,v[10],order[10];
void dfs(int i)
{

    v[i]=comp;
    for(int j=0;j<n;j++)
    if(e[i][j] && i!=j)
     if(!v[j])
       dfs(j);
   order[i]=count--;
   for(int j=0;j<n;j++)
    if(e[i][j] && v[i]==v[j] && v[i]!=0 && v[j]!=0 && order[i]>order[j])
     {
      cout<<"\n The given graph is cyclic.";
      getch();
      exit(0);
      }


}
void main()
{
  int i,j;
  clrscr();
  cout<<"\nEnter the value of n (i.e.),no of vertices:\t";
  cin>>n;count=n;
  cout<<"\n\nEnter the adjacency matrix of digraph.\n";
  for(i=0;i<n;i++)
  for(j=0;j<n;j++)
   scanf("%d",&e[i][j]);
  for(i=0;i<n;i++)
  if(v[i]==0)
    {
     comp+=1;;
     dfs(i);
    }
  cout<<"\ntopological order:\t";
  for(i=0;i<n;i++)
   cout<<"\n vertex [ "<<(i+1)<<" ]\torder:\t"<<order[i];
  getch();
}