BFS

#include <iostream>
#include <list>
using namespace std;

class Graph {
int numVertices;
list<int>* adjLists;
bool* visited;

public:
Graph(int vertices);
void addEdge(int src, int dest);
void BFS(int startVertex);
};

// Create a graph with given vertices, and maintain an adjacency list
Graph::Graph(int vertices) {
numVertices = vertices;
adjLists = new list<int>[vertices];
}
// Add edges to the graph
void Graph::addEdge(int src, int dest) {
adjLists[src].push_back(dest);
adjLists[dest].push_back(src);
}
// BFS algorithm
void Graph::BFS(int startVertex) {
visited = new bool[numVertices];
for (int i = 0; i < numVertices; i++)
visited[i] = false;
list<int> queue;
visited[startVertex] = true;
queue.push_back(startVertex);
list<int>::iterator i;
while (!queue.empty()) {
int currVertex = queue.front();
cout << currVertex << " ";
queue.pop_front();
for (i = adjLists[currVertex].begin(); i != adjLists[currVertex].end(); ++i) {
int adjVertex = *i;
if (!visited[adjVertex]) {
visited[adjVertex] = true;
queue.push_back(adjVertex);
}

}
}
}
int main() {
Graph g(4);
g.addEdge(0, 1);
g.addEdge(0, 2);
g.addEdge(1, 2);
g.addEdge(2, 0);
g.addEdge(2, 3);
g.addEdge(3, 3);
cout << "Breadth -first traversal for the given graph:"<<” “;
g.BFS(2);

return 0;
}