Untitled

#include<stdio.h>

int q[20],front=-1,rear=-1,a[20][20],vis[20];
int delete();
void add(int item); 
void bfs(int s,int n);

void main()
{
int n,e,i,s,j,u,v;

printf("enter the numberof vertices in the graph:");
scanf("%d",&n);
printf("enter the number of edges in the graph:");
scanf("%d",&e);
printf("enter the edges(u,v):\n");
for(i=1;i<=e;i++)
{
scanf("%d%d",&u,&v);
a[u][v]=1;
}
printf("THE ADJACENCY MATRIX IS\n");
for(i=1;i<=n;i++)
{
for(j=1;j<=n;j++)
{
printf("%d",a[i][j]);
}
printf("\n");
}
for(i=1;i<=n;i++)
vis[i]=0;
printf("ENTER THE SOURCE VERTEX:");
scanf("%d",&s);

bfs(s,n);
}

void bfs(int s,int n)
{
int p,i;
add(s);
vis[s]=1;
p=delete();

if(p!=0)
printf("%d",p);
while(p!=0)
{
for(i=1;i<=n;i++)
if((a[p][i]!=0)&&(vis[i]==0))
{
add(i);
vis[i]=1;
}
p=delete();

if(p!=0)
printf("%d",p);
}
for(i=1;i<=n;i++)
if(vis[i]==0)
bfs(i,n);
}
void add(int item)
{
if(rear==19)
printf("QUEUE FULL");
else
{
if(rear==-1)
{
q[++rear]=item;
front++;
}
else
q[++rear]=item;
}
}
int delete()
{
int k;
if((front>rear)||(front==-1))
return(0);
else
{
k=q[front++];
return(k);
}
}