Adjacency List

#include<stdio.h>

#include<stdlib.h>

typedef struct node

{

char data;

struct node *next;

        struct edge *adj;

}node;

typedef struct edge

{

node *dest;

struct edge *link;

}edge;

node *start;

node *get1(char x)

{

node *p;

p=(node *)malloc(sizeof(node));

p->data=x;

p->next=NULL;

p->adj=NULL;

return p;

}

edge *get2()

{

edge *p;

p=(edge *)malloc(sizeof(edge));

p->dest=NULL;

p->link=NULL;

return p;

}

node *create()

{

node *p,*q;

edge *r,*s;

char x,y;

while(1)

{

fflush(stdin);

printf("Enter the node (if no vertex then press only [enter]) : ");

scanf("%c",&x);

if(x=='\n')

break;

p=get1(x);

if(start==NULL)

start=p;

else

q->next=p;

q=p;

printf("\n");

}

p=start;

while(p!=NULL)

{

printf("\n");

while(1)

{

printf("\nEnter the adjacent vertex of %c (if no vertex then press only [enter]) : ",p->data);

fflush(stdin);

scanf("%c",&x);

if(x=='\n')

break;

q=start;

while(q!=NULL)

{

if(x==q->data)

break;

q=q->next;

}

if(q==NULL)

printf("\nPlease enter right value.\n");

else

{

r=get2();

r->dest=q;

if(p->adj==NULL)

p->adj=r;

else

s->link=r;

s=r;

}

}

p=p->next;

}

return start;

}

void display(node *start)

{

node *a;

edge *b;

if(start==NULL)

{

printf("\n\nlink list not exist.\n");

return;

}

a=start;

printf("\n\nThe required result is:- \n");

printf("\n| NODE |  | ADJACENCY LIST \n\n");

while(a!=NULL)

{

printf("|  %c   |  | ",a->data);

b=a->adj;

while(b!=NULL)

{

printf("%c ",b->dest->data);

b=b->link;

}

a=a->next;

printf("\n");

}

}

int main()

{

create();

display(start);

return 1;

}

abhi@hp-15q-laptop:~$ gcc adjacency.c

abhi@hp-15q-laptop:~$ ./a.out

Enter the node (if no vertex then press only [enter]) : A

Enter the node (if no vertex then press only [enter]) : B

Enter the node (if no vertex then press only [enter]) : C

Enter the node (if no vertex then press only [enter]) : D

Enter the node (if no vertex then press only [enter]) : E

Enter the node (if no vertex then press only [enter]) :

Enter the adjacent vertex of A (if no vertex then press only [enter]) : B

Enter the adjacent vertex of A (if no vertex then press only [enter]) : C

Enter the adjacent vertex of A (if no vertex then press only [enter]) : D

Enter the adjacent vertex of A (if no vertex then press only [enter]) :

Enter the adjacent vertex of B (if no vertex then press only [enter]) : C

Enter the adjacent vertex of B (if no vertex then press only [enter]) :

Enter the adjacent vertex of C (if no vertex then press only [enter]) :

Enter the adjacent vertex of D (if no vertex then press only [enter]) : C

Enter the adjacent vertex of D (if no vertex then press only [enter]) : E

Enter the adjacent vertex of D (if no vertex then press only [enter]) :

Enter the adjacent vertex of E (if no vertex then press only [enter]) : C

Enter the adjacent vertex of E (if no vertex then press only [enter]) :

The required result is:-

| NODE |  | ADJACENCY LIST

|     A     |  | B C D

|     B     |  | C

|     C     |  |

|     D     |  | C E

|     E     |  | C