How to implement Dijkstras Algorithm with Adjacency lists - c++

Question

My program is reading input from a text file in the order of
A
B
C
A B 10
A C 5
B A 3
B C 2
C A 4
C B 1
and stores the data into a graph which is represented by an adjacency list. I want to write a program that finds the shortest path from A to all other nodes using Dijkstra's Algorithm.
I have watched several videos but still couldn't quite get how to implement the algorithm as the examples use graphs which are represented as adjacency matrices. Below is the program:
#include <cstdlib>
#include <iostream>
#include <fstream>
#include <locale>
#include <sstream>
#include <string>
#include <vector>
using namespace std;
#define INFINITE -1
/* node */
struct Node
{
char key;
int distance;
Node *next;
};
/* GraphNode */
struct GraphNode
{
char key;
Node *listpointer;
};
/* Add nodes to the front of the list */
void AddNodeToFront(Node*& listpointer, char newkey, int newdistance)
{
Node *temp;
temp = new Node;
temp->key = newkey;
temp->distance=newdistance;
temp->next = listpointer;
listpointer = temp;
}
/* printf LLnodes */
void PrintLLnodes(Node*& listpointer)
{
Node *temp;
temp = listpointer;
while(temp!=NULL)
{
printf("to node %c dist: %d \n", temp->key, temp->distance);
temp=temp->next;
}
}
/* Implement the Graph class */
class Graph
{
private:
vector<GraphNode> adjlist;
int totalgraphnodes;
public:
Graph(){totalgraphnodes = 0;}
~Graph(){}
void AddNewGraphNode(char newgraphnode);
void AddNewEdgeBetweenGraphNodes(char A, char B, int distance);
void PrintAllGraphNodesWithCosts();
void DijkstrasAlgorithm(char sourcenode);
int GetTotalNodes() { return totalgraphnodes; }
};
/* graph class functions */
void Graph::AddNewGraphNode(char newgraphnode){
totalgraphnodes++;
GraphNode temp;
temp.key=newgraphnode;
temp.listpointer = NULL;//important
adjlist.push_back(temp);
}
void Graph::AddNewEdgeBetweenGraphNodes(char A, char B, int distance)
{
//find which node A is
int a;
for (a = 0;adjlist.size();a++)
{
if (A == adjlist[a].key) break;
}
AddNodeToFront(adjlist[a].listpointer, B, distance);
}
void Graph::PrintAllGraphNodesWithCosts()
{
for (unsigned int a = 0;a < adjlist.size();a++){
printf("From Node %c: \n", adjlist[a].key);
PrintLLnodes(adjlist[a].listpointer);
}
}
**// implement Dijkstra's Algorithm
void Graph::DijkstrasAlgorithm(char sourcenode)**
{
int distance[adjlist.size()];
char state[adjlist.size()];
// setting the initial distance and state of the first node
distance[0] = 0;
state[0] = 'p';
// assigning all distance and state to temp and infinite
for(int i = 1; i <= adjlist.size(); i++)
{
distance[i] = INFINITE;
state[i] = 't';
}
// get the sourcenode from the adjlist in Graph
unsigned int a;
for(a = 0; a <= adjlist.size(); a++)
{
if(sourcenode == adjlist[a].key) { break; } // break when found 'A'
}
// assign sourcenode listpointer to current
Node *current;
current = adjlist[a].listpointer;
bool stilltempvertex = true;
while(stilltempvertex) {}
}
/* declare a new Graph */
Graph mygraph;
main( /*int argc, char** argv */)
{
/* call Dijkstra */
mygraph.DijkstrasAlgorithm('A'); //always from A in this program
/* Print answer in the required format */
}
As far as implementation is concerned, all the nodes and edges are read correctly (I have ommited some code to allow for readability, but mygraph has nodes A, B, C and the corresponding edges.), its just that I cant seem to figure out how to properly implement the algorithm for this one.
The nodes are readfrom the file and stored in a vector ajdlist. Each graphnode then has its own linked list which points to adjacent nodes in the graph.
Anyone could take me step by step through with the algorithm implementation on this? Thanks in advance.