Added cpp file BFSforgraphtree

BFSforgraphtree.cpp

@@ -0,0 +1,56 @@
+/* Author- Amar Singh */
+#include<iostream>
+#include<vector>
+#include<queue>
+
+using namespace std;
+/* This is for undirected graph, Remove the second condition for Directed Graph */
+void addEdge(vector<int>* graph, int u, int v)
+{
+	graph[u].push_back(v);
+	graph[v].push_back(u);   // for Undirected Graph
+}
+
+int main()
+{
+	int n; //vertices
+	int e; //edges
+	int v, u;  
+	cout<< "Enter Size of Vertices \n";
+	cin>> n;
+	cout<< "Enter Size of Edges \n";
+	cin>> e;
+	int copy;
+	copy= n;
+	int a[n+1]= {0}; //array for node visited or not
+	vector<int> graph[n+1]; 
+	for(int i=1; i<=e; i++)
+	{
+		cout<<"From ";
+		cin>>u;
+		cout<<"To ";
+		cin>>v;
+		addEdge(graph,u,v); 
+	}
+	vector<int>::iterator it; 
+	queue<int> q;
+	q.push(1); 
+	a[1] = 1; 
+	int x;
+	cout<<"BFS is\n";
+	while(!q.empty())
+	{
+		x = q.front();
+		q.pop();
+		cout<<x <<" ";
+		for(it=graph[x].begin(); it!=graph[x].end(); it++)
+		{
+			if(a[*it]!=1)
+			{
+				q.push(*it);
+				a[*it]=1;
+			}
+		}
+	}
+	return 0;
+}