The code implements an adjacency list representation of a graph as a class. The class contains structs to represent graph nodes and edges. Methods are defined to create a graph, add edges, and print the graph. The main function creates a graph, adds edges, and prints the graph by calling the class methods.

1. // This code currently works... Run it and get a screen shot of its
output.
// Next, Convert this code to a class. Have the class in the same
file as the int main.
#include "stdafx.h"
#include <stdio.h>
#include <stdlib.h>
#include <iostream>
using namespace std;
struct AdjListNode
{
int dest;
struct AdjListNode* next;
};
struct AdjList
{
struct AdjListNode *head;
};
struct Graph
{
int V;
struct AdjList* array;
};
struct AdjListNode * newAdjListNode(int dest)
{
struct AdjListNode * newNode = new AdjListNode;
newNode->dest = dest;
newNode->next = NULL;
return newNode;
}

2. struct Graph* createGraph(int V)
{
struct Graph* graph = new Graph;
graph->V = V;
graph->array = new AdjList;
int i;
for (i = 0; i < V; ++i)
graph->array[i].head = NULL;
return graph;
}
void addEdge(struct Graph* graph, int src, int dest)
{
struct AdjListNode* newNode = newAdjListNode(dest);
newNode->next = graph->array[src].head;
graph->array[src].head = newNode;
newNode = newAdjListNode(src);
newNode->next = graph->array[dest].head;
graph->array[dest].head = newNode;
}
void printGraph(struct Graph* graph)
{
int v;
for (v = 0; v < graph->V; ++v)
{
struct AdjListNode* pCrawl = graph->array[v].head;
cout << endl << "Adjacency list of vertex " << v <<
endl << " head";
while (pCrawl)
{

3. cout << "-> " << pCrawl->dest;
pCrawl = pCrawl->next;
}
cout << endl;
}
}
int main()
{
int V = 5;
struct Graph* graph = createGraph(V);
addEdge(graph, 0, 1);
addEdge(graph, 0, 4);
addEdge(graph, 1, 2);
addEdge(graph, 1, 3);
addEdge(graph, 1, 4);
addEdge(graph, 2, 3);
addEdge(graph, 3, 4);
printGraph(graph);
system("pause");
return 0;
}
Solution
Now the code has been converted into the Class:
#include "stdafx.h"
#include <stdio.h>

4. #include <stdlib.h>
#include <iostream>
using namespace std;
class GraphImplementaion
{
public:
struct AdjListNode {
int dest;
struct AdjListNode* next;
};
public:
struct AdjList
{
struct AdjListNode *head;
};
public:
struct Graph
{
int V;
struct AdjList* array;
};
public:
struct AdjListNode * newAdjListNode(int dest)
{

5. struct AdjListNode * newNode = new AdjListNode;
newNode->dest = dest;
newNode->next = NULL;
return newNode;
}
public:
struct Graph* createGraph(int V)
{
struct Graph* graph = new Graph;
graph->V = V;
graph->array = new AdjList;
int i;
for (i = 0; i < V; ++i)
graph->array[i].head = NULL;
return graph;
}
public:
void addEdge(struct Graph* graph, int src, int dest)
{
struct AdjListNode* newNode = newAdjListNode(dest);
newNode->next = graph->array[src].head;
graph->array[src].head = newNode;
newNode = newAdjListNode(src);
newNode->next = graph->array[dest].head;
graph->array[dest].head = newNode;

6. }
public:
void printGraph(struct Graph* graph)
{
int v;
for (v = 0; v < graph->V; ++v)
{
struct AdjListNode* pCrawl = graph->array[v].head;
cout << endl << "Adjacency list of vertex " << v << endl <<
" head";
while (pCrawl)
{
cout << "-> " << pCrawl->dest;
pCrawl = pCrawl->next;
}
cout << endl;
}
}
int main()
{
GraphImplementaion GI;
int V = 5;
GI.struct Graph* graph = createGraph(V);
GI.addEdge(graph, 0, 1);

7. GI.addEdge(graph, 0, 4);
GI.addEdge(graph, 1, 2);
GI.addEdge(graph, 1, 3);
GI.addEdge(graph, 1, 4);
GI.addEdge(graph, 2, 3);
GI.addEdge(graph, 3, 4);
GI.printGraph(graph);
system("pause");
return 0;
}