Graphs in C++

Author: suresh-srivastava

Diff for: Graphs/adjacency-list/DirectedGraphList.cpp

@@ -0,0 +1,214 @@
+//Copyright (C) Suresh Kumar Srivastava - All Rights Reserved
+//DSA Masterclass courses are available on CourseGalaxy.com
+
+//DirectedGraph.cpp : Program for directed graph using adjacency matrix.
+
+#include<iostream>
+#include<string>
+using namespace std;
+
+static const int maxSize = 30;
+
+class Vertex
+{
+	public:
+		string name;
+
+	public:
+		Vertex(string name)
+		{
+			this->name = name;
+		}
+};//End of class Vertex
+
+class DirectedGraph
+{
+	private:
+		int nVertices;
+		int nEdges;
+		int adj[maxSize][maxSize];
+		Vertex *vertexList[maxSize];
+
+	private:
+		int getIndex(string vertexName);
+		bool isAdjacent(int u, int v);
+
+	public:
+		DirectedGraph();
+		~DirectedGraph();
+		void insertVertex(string vertexName);
+		void insertEdge(string source, string destination);
+		void deleteEdge(string source, string destination);
+		void display();
+		bool edgeExists(string source, string destination);
+		int getOutdegree(string vertex);
+		int getIndegree(string vertex);
+
+};//End of class DirectedGraph
+
+DirectedGraph::DirectedGraph()
+{
+	nVertices = 0;
+	nEdges = 0;
+
+	for(int i=0; i<maxSize; i++)
+	{
+		for(int j=0; j<maxSize; j++)
+		{
+			adj[i][j] = 0;
+		}
+	}
+}//End of DirectedGraph()
+
+DirectedGraph::~DirectedGraph()
+{
+	for(int i=0; i<nVertices; i++)
+	{
+		delete vertexList[i];
+	}
+}//End of ~DirectedGraph()
+
+void DirectedGraph::insertVertex(string vertexName)
+{
+	vertexList[nVertices++] = new Vertex(vertexName);
+}//End of insertVertex()
+
+int DirectedGraph::getIndex(string vertexName)
+{
+	for(int i=0; i<nVertices; i++ )
+	{
+        if(vertexName == vertexList[i]->name)
+            return i;
+	}
+
+	throw exception("Invalid Vertex");
+
+}//End of getIndex()
+
+void DirectedGraph::insertEdge(string source, string destination)
+{
+	int u = getIndex(source);
+	int v = getIndex(destination);
+            
+	if(u == v)
+		cout << "Not a valid edge\n";
+	else if(adj[u][v] != 0)
+		cout << "Edge already present\n";
+	else  
+	{
+		adj[u][v] = 1;
+		nEdges++;
+	}
+}//End of insertEdge()
+
+void DirectedGraph::deleteEdge(string source, string destination)
+{
+	int u = getIndex(source);
+	int v = getIndex(destination);
+
+	if(adj[u][v] != 0)
+	{
+		adj[u][v] = 0;
+		nEdges--;
+	}
+	else
+	{
+		cout << "Edge doesn't exist\n";
+	}
+}//End of deleteEdge()
+
+void DirectedGraph::display()
+{
+    for(int i=0; i<nVertices; i++)
+    {
+     	for(int j=0; j<nVertices; j++)
+			cout << adj[i][j] << " ";
+        cout <<"\n";
+    }
+}//End of display()
+
+bool DirectedGraph::isAdjacent(int u, int v)
+{
+	return (adj[u][v] != 0);
+}//End of isAdjacent()
+
+bool DirectedGraph::edgeExists(string source, string destination)
+{
+	return isAdjacent(getIndex(source), getIndex(destination));
+}//End of edgeExists()
+
+//Returns number of edges going out from a vertex
+int DirectedGraph::getOutdegree(string vertex)
+{
+	int u = getIndex(vertex);
+
+	int outdegree = 0;
+    for(int v = 0; v<nVertices; v++)
+	{
+        if(adj[u][v] != 0)
+			outdegree++;
+	}
+
+    return outdegree;
+}//End of getOutdegree()
+   
+//Returns number of edges coming to a vertex
+int DirectedGraph::getIndegree(string vertex)
+{
+    int u = getIndex(vertex);
+   
+    int indegree = 0;
+    for(int v=0; v<nVertices; v++)
+	{
+        if(adj[v][u] != 0)
+            indegree++;
+	}
+
+    return indegree;
+}//End of getIndegree()
+
+int main()
+{
+	DirectedGraph dGraph;
+
+	try
+	{
+		//Creating the graph, inserting the vertices and edges
+		dGraph.insertVertex("0");
+		dGraph.insertVertex("1");
+		dGraph.insertVertex("2");
+		dGraph.insertVertex("3");
+
+		dGraph.insertEdge("0","3");
+		dGraph.insertEdge("1","2");
+		dGraph.insertEdge("2","3");
+		dGraph.insertEdge("3","1");
+		dGraph.insertEdge("0","2");
+
+		//Display the graph
+		dGraph.display();
+		cout << "\n";
+
+		//Deleting an edge
+		dGraph.deleteEdge("0","2");
+
+		//Display the graph
+		dGraph.display();
+
+		//Check if there is an edge between two vertices
+		cout << "Edge exist : " << (dGraph.edgeExists("2","3") ? "True" : "False") << "\n";
+
+		//Display Indegree and Outdegree of a vertex
+		cout << "Outdegree : " << dGraph.getOutdegree("3") << "\n";
+		cout << "Indegree : " << dGraph.getIndegree("3") << "\n";
+
+	}//End of try
+	catch(exception e)
+	{
+		cout << e.what() << "\n";
+	}
+
+	return 0;
+
+}//End of main()
+