Bfs for graph

C++/bfs.cpp

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+#include <iostream>
+#include <bits/stdc++.h>
+
+using namespace std;
+
+vector<bool> v;
+vector<vector<int>> g;
+
+void bfsTraversal(int b)
+{
+    //Declare a queue to store all the nodes connected to b
+    queue<int> q;
+
+    //Insert b to queue
+    q.push(b);
+
+    //mark b as visited
+    v[b] = true;
+
+    cout << "\n\nThe BFS Traversal is:  ";
+
+    while (!q.empty())
+    {
+        int a = q.front();
+        q.pop(); //delete the first element form queue
+
+        for (auto j = g[a].begin(); j != g[a].end(); j++)
+        {
+            if (!v[*j])
+            {
+                v[*j] = true;
+                q.push(*j);
+            }
+        }
+        cout << a << "  ";
+    }
+}
+
+void makeEdge(int a, int b)
+{
+    g[a].push_back(b); //an edge from a to b (directed graph)
+}
+
+int main()
+{
+    cout << "\n\nWelcome to Studytonight :-)\n\n\n";
+    cout << " =====  Program to demonstrate the Breadth First Search Algorithm, in CPP  ===== \n\n";
+
+    cout << " =====  Note; The vertices are numbered from 0 to n-1.  ===== \n\n";
+
+    int n, e;
+
+    cout << "Enter the number of vertices: ";
+
+    cin >> n;
+
+    cout << "\n\nEnter the number of edges: ";
+
+    cin >> e;
+
+    v.assign(n, false);
+    g.assign(n, vector<int>());
+
+    int a, b, i;
+
+    cout << "Enter the edges with source and target vetex: \n ";
+
+    for (i = 0; i < e; i++)
+    {
+        cin >> a >> b;
+        makeEdge(a, b);
+    }
+
+    for (i = 0; i < n; i++)
+    {
+        //if the node i is unvisited
+        if (!v[i])
+        {
+            bfsTraversal(i);
+        }
+    }
+
+    cout << "\n\n\n";
+
+    return 0;
+}