Dijkstra Algorithm using the priority queue

#include <bits/stdc++.h>  
using namespace std;  
#define INF 0x3f3f3f3f // The distance to other vertices is initialized as infinite  
// iPair ==> Integer Pair  
typedef pair<int, int> iPair;  
class Graph // Graph structure  
    {  
    int V; // No. of vertices in the graph  
    list<pair<int, int>>* adj; // the list of pair to store vertex and its weight  
public:  
    // Constructor that accept number of vertices in graph  
    Graph(int V) // allocate the vertex memory  
    {  
        this->V = V; // assign the vertex   
        adj = new list<iPair>[V]; // allocate space for vertices   
    }  
    void addEdge(int u, int v, int w); // add edges in the graph  
    // prints shortest path from s  
    void shortestPathingraph(int s); // pass source vertex  
};  
void Graph::addEdge(int u, int v, int w) // add an edge  
{  
    adj[u].push_back(make_pair(v, w)); // make a pair of vertex and weight and // add it to the list  
    adj[v].push_back(make_pair(u, w)); // add oppositely by making a pair of weight and vertex  
}  
// Calling function outside the Graph class  
void Graph::shortestPathingraph(int src) // src is the source vertex  
{  
    // Create a priority queue to store vertices that  
    // are being preprocessed.  
    priority_queue<iPair, vector<iPair>, greater<iPair>> pq;  
    vector<int> dist(V, INF); // All distance from source are infinite  
    pq.push(make_pair(0, src)); // push spurce node into the queue  
    dist[src] = 0; // distance of source will be always 0  
    while (!pq.empty()) { // While queue is not empty  
        // Extract the first minimum distance from the priority queue  
        // vertex label is stored in second of pair (it  
        // has to be done this way to keep the vertices  
        // sorted distance  
        int u = pq.top().second;  
        pq.pop();  
        // 'i' is used to get all adjacent vertices of a vertex  
        list<pair<int, int>>::iterator i;  
        for (i = adj[u].begin(); i != adj[u].end(); ++i) {  
            // Get vertex label and weight of current adjacent  
            // of u.  
            int v = (*i).first;  
            int weight = (*i).second;  
  
            // If there is shorted path to v through u.  
            if (dist[v] > dist[u] + weight) {  
                // Updating distance of v  
                dist[v] = dist[u] + weight;  
                pq.push(make_pair(dist[v], v));  
            }  
        }  
    }  
    printf("Vertex \tDistance from Source\n"); // Print the result  
    for (int i = 0; i < V; ++i)  
        printf("%d \t\t %d\n", i, dist[i]); // The shortest distance from source  
}  
int main()  
{  
    int V = 9; // vertices in given graph are 9  
    Graph g(V); //  call Constructor by creating an object of graph  
    g.addEdge(0, 1, 4); // add root node with neighour vertex and weight  
    g.addEdge(0, 7, 8);  
    g.addEdge(1, 2, 8);  
    g.addEdge(1, 7, 11);  
    g.addEdge(2, 3, 7);  
    g.addEdge(2, 8, 2);  
    g.addEdge(2, 5, 4);  
    g.addEdge(3, 4, 9);  
    g.addEdge(3, 5, 14);  
    g.addEdge(4, 5, 10);  
    g.addEdge(5, 6, 2);  
    g.addEdge(6, 7, 1);  
    g.addEdge(6, 8, 6);  
    g.addEdge(7, 8, 7);  
    g.shortestPathingraph(0); // call the function to find shortest path of graph  
    return 0; // end of main function()  
}