DS – Program to Create Graph

Structures creations representing Vetex and Edge:

struct Vertex {             int data, status;             struct Vertex *next;             struct Edge *adj; };   struct Edge  {             struct Vertex *next;             struct Edge *adj; };

Variables required constructing the Graph:

struct Vertex *start,*p,*q; struct Edge *l,*k;

Physical representation v/s Logical representation:

The internal representation of Graph structure:

void create() {             int data, flag=0;             start = NULL;             printf(“Enter nodes (0 to stop) : \n”);             while(1)             {                         scanf(“%d”, &data);                         if(data==0)                                     break;                                                 p = (struct Vertex*)malloc(sizeof(struct Vertex));                         p->data = data;                         p->status = 0;                         p->next = NULL;                         p->adj = NULL ;                                                 if(flag==0){                                     start = p;                                     q = p;                                     flag++;                         }                         else{                                     q->link = p;                                     q = p;                          }             }

p = start;             while(p != NULL)             {                         printf(“Enter links to %d : (0 to stop) :”, p->data);                         flag=0;                         while(1){                                     scanf(“%d”, &data);                                     if(data==0)                                                 break;                                     k = (struct Edge*)malloc(sizeof(struct Edge));                                     k->adj = NULL;                                                                         if(flag==0){                                                 p->adj = k;                                                 l = k;                                                 flag++;                                     }                                     else{                                                 l->adj = k;                                                 l = k;                                        }                                     q = start;                                     while(q){                                                 if(q->data == data)                                                 {                                                             k->next = q;                                                                break;                                                 }                                                 q=q->next;                                     }                         }                         p=p->next;             } }