Algorithm
- 
Graph Class: - Create a class to represent the graph.
- Include data members to store vertices and edges.
- Use an adjacency list or adjacency matrix to represent connections between vertices.
 
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Vertex Class: - Create a class to represent vertices.
- Include necessary data members like vertex value, and any additional information.
 
- 
Edge Class: - Create a class to represent edges.
- Include data members like source vertex, destination vertex, and any additional information.
 
- 
Graph Operations: - Implement methods to add vertices and edges to the graph.
- Implement methods to remove vertices and edges from the graph.
- Implement methods to check if a vertex or edge exists in the graph.
 
- 
Traversal Algorithms: - Implement depth-first search (DFS) algorithm to traverse the graph.
- Implement breadth-first search (BFS) algorithm to traverse the graph.
 
- 
Shortest Path Algorithms: - Implement algorithms like Dijkstra's or Bellman-Ford to find the shortest path between two vertices.
 
- 
Topological Sorting: - Implement algorithms like Kahn's or DFS-based to perform topological sorting.
 
- 
Minimum Spanning Tree: - Implement algorithms like Prim's or Kruskal's to find the minimum spanning tree of the graph.
 
- 
Graph Representation: - Decide on a representation (adjacency list, adjacency matrix) and implement the necessary data structures accordingly.
 
- 
Error Handling: - Implement appropriate error handling for cases such as adding duplicate vertices, non-existing vertices in edges, etc.
 
- 
Testing: - Develop a set of test cases to validate the correctness of your graph implementation.
 
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Documentation: - Add comments and documentation to explain the purpose and usage of each class and method in your graph implementation.
 
Code Examples
#1 Code Example- Implement Graph Data Structure
Code -
                                                        Java Programming
class Graph {
  // inner class
  // to keep track of edges
  class Edge {
    int src, dest;
  }
  // number of vertices and edges
  int vertices, edges;
  // array to store all edges
  Edge[] edge;
  Graph(int vertices, int edges) {
    this.vertices = vertices;
    this.edges = edges;
    // initialize the edge array
    edge = new Edge[edges];
    for(int i = 0; i  <  edges; i++) {
      // each element of the edge array
      // is an object of Edge type
      edge[i] = new Edge();
    }
  }
  public static void main(String[] args) {
    // create an object of Graph class
    int noVertices = 5;
    int noEdges = 8;
    Graph g = new Graph(noVertices, noEdges);
    // create graph
    g.edge[0].src = 1;   // edge 1---2
    g.edge[0].dest = 2;
    g.edge[1].src = 1;   // edge 1---3
    g.edge[1].dest = 3;
    g.edge[2].src = 1;   // edge 1---4
    g.edge[2].dest = 4;
    g.edge[3].src = 2;   // edge 2---4
    g.edge[3].dest = 4;
    g.edge[4].src = 2;   // edge 2---5
    g.edge[4].dest = 5;
    g.edge[5].src = 3;   // edge 3---4
    g.edge[5].dest = 4;
    g.edge[6].src = 3;   // edge 3---5
    g.edge[6].dest = 5;
    g.edge[7].src = 4;   // edge 4---5
    g.edge[7].dest = 5;
    // print graph
    for(int i = 0; i  <  noEdges; i++) {
      System.out.println(g.edge[i].src + " - " + g.edge[i].dest);
    }
  }
}Output
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Demonstration
Java Programing Example to Implement the graph data structure-DevsEnv
