comp conexe (bf ca subprogram)

///componente conexe
#include <iostream>
#include <fstream>
using namespace std;
int c[100], a[100][100], n,nc=0,u;
bool viz[100];
void citire()
{
    ifstream f("graf.in");
    f>>n;
    for (int i=1; i<=n; ++i)
        for(int j=1; j<=n; j++)
            f>>a[i][j];
}
void BF(int start)
{
    int i, x,p;
    p=u=1;
    c[p]=start;
    viz[start]=true;
    nc++;
    while(p<=u)
    {
        x=c[p];
        for(i=1; i<=n; i++)
            if(a[i][x]==1 && viz[i]==false)
            {
                viz[i]=true;
                u++;
                c[u]=i;
            }
        p++;
    }
}
int main()
{
    int p, b, start, i,x;
    citire();
    for(start=1; start<=n; ++start)
    {
        if(!viz[start])
        {
            BF(start);
            cout<<"componenta conexa "<<nc<<endl;
            for (i=1; i<=u; i++)
                cout<<c[i]<<" ";
            cout<<endl<<endl;
        }
    }
    cout<<"Graful are "<<nc<<" elemente conexe.\n";
}
/*graf.in
7
0 0 1 1 0 0 0
0 0 0 0 0 1 0
1 0 0 0 0 0 0
1 0 0 0 0 0 1
0 0 0 0 0 0 0
0 1 0 0 0 0 0
0 0 0 1 0 0 0
*/