find strongly connected components in a directed graph using kosaraju's algorithm

stronglyconnected.cpp

#include<iostream>
#include<stack>
#define initial 0
#define visited 1
#define finished 2
using namespace std;

int adj[10][10];
int rev_adj[10][10];
int state[10];
stack<int> st;
void create_graph(int n,int m)
{
    int i,j,k,src,dest;

      for(j=0;j<n;j++)
     {
         for(k=0;k<n;k++)
         {
             adj[j][k]=0;
         }
     }

     for(i=0;i<m;i++)
     {
         cout<<"enter the source and destination \n";
         cin>>src>>dest;

         if(src<0||src>=n||dest<0||dest>=n)
         {
             cout<<"invalid vertex \n";
             i--;
         }

         adj[src][dest]=1;
     }

     for(j=0;j<n;j++)
     {
         for(k=0;k<n;k++)
         {
             cout<<adj[j][k]<<"\t";
         }
         cout<<endl;
     }
}
void DFS_traversal(int s,int n,int t_no)
{
    int i;
    cout<<s<<"\t";
    state[s]=visited;
    if(t_no==1)
    {
        for(i=0;i<n;i++)
        {
            if(adj[s][i]==1&&state[i]==initial)
                DFS_traversal(i,n,t_no);
        }
    }
    else
    {
        for(i=0;i<n;i++)
        {
            if(rev_adj[s][i]==1&&state[i]==initial)
                DFS_traversal(i,n,t_no);
        }
    }
    state[s]=finished;
    if(t_no==1)
    st.push(s);
}

void find_components(int n)
{
    int a,b;
    cout<<endl<<"reverse graph--\n";
     for(a=0;a<n;a++)
     {
         for(b=0;b<n;b++)
         {
             rev_adj[a][b]=adj[b][a];
         }
     }
     for(a=0;a<n;a++)
     {
         for(b=0;b<n;b++)
         {
             cout<<rev_adj[a][b]<<"\t";
         }
         cout<<endl;
     }
     cout<<"components are\n";
     while(!st.empty())
     {
         int q=st.top();
         st.pop();
         if(state[q]==initial)
            {
                DFS_traversal(q,n,2);
                cout<<endl;
            }
     }

}
int main()
{
    int n,m,s,z;
    cout<<"enter the no of vertices \n";
    cin>>n;
    cout<<"Enter the number of edges\n";
    cin>>m;
    create_graph(n,m);
    for(z=0;z<n;z++)
    {
        state[z]=initial;
    }
    cout<<"enter the starting vertex \n";
    cin>>s;
    cout<<endl;
    DFS_traversal(s,n,1);
    cout<<endl;
    for(z=0;z<n;z++)
    {
        state[z]=initial;
    }
    find_components(n);

}