Breadth First Traversal, without using queue.

BFS, with layers

#define nodecount 10000
bool discovered[nodecount];
vector<vector<int> > L;//Layers
void BFS(int s, vector<vector<int, int> > & adjList)//BFS for arrays, without queue, non-recursive, by @arkanathpathak
{
    fill(discovered, discovered+nodecount, false);
    discovered[s] = true;
    for(int v=0;v<nodecount;v++)
    {
        if(v!=s)discovered[v]=false;
    }
    int i=0;
    L.push_back(*(new vector<int>));
    L[0].push_back(s);
    while(L[i].size()!=0)
    {
        L.push_back(*(new vector<int>));
        for(int j=0;j < (int)L[i].size(); j++)
        {
            int u = L[i][j];
            for(int k=0;k<(int)adjList[u].size();k++)
            {
                int v = adjList[u][k];
                if(discovered[v]==false)
                {
                    discovered[v] = true;
                    L[i+1].push_back(v);
                }
            }
        }
        i++;
    }
}