Topological Sort using DFS & Transpose Matrix

#include<iostream>
#include<list>
#include<queue>
using namespace std;
int v,t;
int matrix[100][100];
int GT[101][101];
int clr[100],dis[100],fin[100],prev[100];
int t_edge,b_edge,f_edge,c_edge;
list <int> tp_sort;
list <int> :: iterator it;
void DFS();
void DFS_visit(int s);
void SCC();
int main()
{
    int r,c,n,s;
    int edge=1;
    cout<<"Input No Of Vertices: ";
    cin>>v;

    do
    {
        cout<<"Edge "<<edge<<": "<<endl;
        cin>>r>>c;

        if(r>v || c>v)
            cout<<"Invalid Input"<<endl;
        else
        {
            matrix[r][c]=1;
            edge++;
        }
    }while(r!=0 && c!=0);

    DFS();
    if(b_edge>0)
        cout<<endl<<"Cyclic Graph!! Topological Sort Is Not Possible"<<endl;
    else
    {
        cout<<endl<<endl<<"Topological sort: ";
        for(it=tp_sort.begin();it!=tp_sort.end();it++)
            cout<<*it<<" ";
    }
    cout<<endl;
    SCC();
    return 0;
}

void DFS()
{
    int i;
    t=0;
    t_edge=0;
    b_edge=0;
    f_edge=0;
    c_edge=0;

    for(i=0;i<=v;i++)
    {

        dis[i]=2000000;
        fin[i]=2000000;
        clr[i]=0;
        prev[i]=-1;
    }

for(i=1;i<=v;i++){
    if(clr[i]==0)
    {
        DFS_visit(i);
    }
}
    cout<<endl<<"Vertex: ";
    for(i=1;i<=v;i++)
        cout<<i<<" ";
    cout<<endl<<"dis[u]: ";
    for(i=1;i<=v;i++)
        cout<<dis[i]<<" ";
    cout<<endl<<"fin[u]: ";
    for(i=1;i<=v;i++)
        cout<<fin[i]<<" ";
   cout<<endl;
   cout<<endl;
   cout<<endl;



        cout<<"No Of Tree Edges: "<<t_edge<<endl;
        cout<<"No Of forward Edges: "<<f_edge<<endl;
        cout<<"No Of Back Edges: "<<b_edge<<endl;
        cout<<"No Of cross Edges: "<<c_edge<<endl;

}

void DFS_visit(int s)
{
    int i;
    clr[s]=1;
    //t=t+1;
    dis[s]=++t;
    for(i=1;i<=v;i++)
    {
        if(matrix[s][i]==1 && clr[i]==2)
        {
            if(dis[s]<dis[i])
            {
                f_edge++;
                cout<<s<<"-"<<i<<": Forward Edge"<<endl;
            }

        else
        {
            c_edge++;
            cout<<s<<"-"<<i<<": Cross Edge"<<endl;
        }
    }
        else if(matrix[s][i]==1 && clr[i]==1)
        {
            b_edge++;
            cout<<s<<"-"<<i<<": Back Edge"<<endl;
        }
        else
        {
            if(matrix[s][i]==1 && clr[i]==0)
            {
                prev[i]=s;
                cout<<s<<"-"<<i<<": Tree Edge"<<endl;
                t_edge++;
                DFS_visit(i);
            }
        }
    }

    clr[s]=2;
    fin[s]=++t;
    tp_sort.push_front(s);


}

void SCC()
{
    int i,j;
    for(i=1;i<=v;i++)
    {
        for(j=1;j<=v;j++)
            GT[j][i]=matrix[i][j];

    }
    cout<<"The Transposed Matrix Is: "<<" "<<endl;
    for(int i=1;i<=v;i++)
    {
        for(int j=1;j<=v;j++)
        {
            cout<<" "<<GT[i][j]<<" ";
        }
        cout<<endl;
    }


}