adj&visited.cpp

#include <iostream>
using namespace std;

class Graph {
    int **adjMatrix;
    int vertices;

public:
    void createGraph(int v, int e) {
        vertices = v;
        adjMatrix = new int*[vertices];

        for (int i = 0; i < vertices; i++) {
            adjMatrix[i] = new int[vertices];

            for (int j = 0; j < vertices; j++) {
                adjMatrix[i][j] = 0; // Initialize adjacency matrix with 0
            }
        }

        int u, ver;
        for (int i = 0; i < e; i++) {
            cout << "Enter edge " << i + 1 << " (format: u v): ";
            cin >> u >> ver;

            if (u < 0 || u >= vertices || ver < 0 || ver >= vertices) {
                cout << "Invalid edge! Vertex numbers should be between 0 and " << vertices - 1 << ".\n";
                i--; 
                continue;
            }

            adjMatrix[u][ver] = 1;
            adjMatrix[ver][u] = 1; // Remove this line for a directed graph
        }
    }

    bool isVisited(int vertex) {
        if (vertex < 0 || vertex >= vertices) {
            cout << "Invalid vertex number!\n";
            return false;
        }

        // Check if the vertex has at least one connection (row or column has a 1)
        for (int i = 0; i < vertices; i++) {
            if (adjMatrix[vertex][i] == 1 || adjMatrix[i][vertex] == 1) {
                return true;
            }
        }
        return false;
    }

    void checkVisited() {
        int vertex;
        cout << "Enter a vertex to check if visited: ";
        cin >> vertex;

        if (isVisited(vertex)) {
            cout << "Vertex " << vertex << " has been visited (it is connected to another vertex).\n";
        } else {
            cout << "Vertex " << vertex << " has NOT been visited (it is isolated).\n";
        }
    }

    void deleteGraph() {
        for (int i = 0; i < vertices; i++) {
            delete[] adjMatrix[i];
        }
        delete[] adjMatrix;
    }
};

int main() {
    Graph g;
    int v, e;
    cout << "Enter number of vertices: ";
    cin >> v;
    cout << "Enter number of edges: ";
    cin >> e;
    
    g.createGraph(v, e);

    while (true) {
        g.checkVisited();
        char choice;
        cout << "Do you want to check another vertex? (y/n): ";
        cin >> choice;
        if (choice != 'y' && choice != 'Y') break;
    }

    g.deleteGraph();
    return 0;
}