Adjacency

#include <stdio.h>

#define V 4

int main() { int adj[V][V] = {0};

adj[0][1] = adj[1][0] = 1; // A-B
adj[0][2] = adj[2][0] = 1; // A-C
adj[1][3] = adj[3][1] = 1; // B-D

printf("Adjacency Matrix (Undirected):\n");
printf("    A B C D\n");
for (int i = 0; i < V; i++) {
    printf("%c | ", 'A' + i);
    for (int j = 0; j < V; j++) {
        printf("%d ", adj[i][j]);
    }
    printf("\n");
}

return 0;

}

#include <stdio.h> #include <stdlib.h>

#define V 4

struct Node { int dest; struct Node* next; };

struct Graph { struct Node* adj[V]; };

struct Node* newNode(int dest) { struct Node* node = (struct Node*)malloc(sizeof(struct Node)); node->dest = dest; node->next = NULL; return node; }

void addEdge(struct Graph* g, int u, int v) { struct Node* node = newNode(v); node->next = g->adj[u]; g->adj[u] = node; }

// Print the adjacency list void printGraph(struct Graph* g) { printf("Adjacency List (Directed):\n"); for (int i = 0; i < V; i++) { printf("%c -> ", 'A' + i); struct Node* temp = g->adj[i]; while (temp) { printf("%c ", 'A' + temp->dest); temp = temp->next; } printf("\n"); } }

int main() { struct Graph g = {0};

addEdge(&g, 0, 1); // A->B
addEdge(&g, 0, 2); // A->C
addEdge(&g, 1, 3); // B->D

printGraph(&g);

return 0;

}