// Include the Algorithm to be used.
  #include "Algorithms/DijkstrasDistanceAlgorithm.h";
  #include "Utils/Graph.h"
  #include <iostream>

1. Dijkstra's Algorithm - Returns the length of the shortest path from a source vertex to every other vertex in the graph.  

  // Create an empty directed graph A.
  Graph G('A', 'D');
 
  // Add vertices and edges to the directed graph G.
  G.add_edge('b', 'a', 15);
  G.add_edge('b', 'c', 10);
  G.add_edge('d', 'c', 10);
  G.add_edge('d', 'g', 1);
  G.add_edge('g', 'f', 2);
  G.add_edge('f', 'e', 1);
  G.add_edge('d', 'e', 8);
  G.add_edge('b', 'd', 2);
  G.add_edge('b', 'g', 6);
  G.add_edge('g', 'a', 4);
  G.add_edge('f', 'a', 7);
  G.add_edge('e', 'c', 2);

  // Compute the distance from vertex b to every other vertex in G.
  map<char, int> distances_map = dijkstras_distances('b', G);

L(a) = 7
L(b) = 0
L(c) = 8
L(d) = 2
L(e) = 6
L(f) = 5
L(g) = 3