Write a program to implement BFS/ DFS routine in a connected graph

Write a program to implement BFS/ DFS routine in a connected
graph

Question Posted / tanuja panda

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Write a program to implement BFS/ DFS routine in a connected graph..

Answer / akshay p

#include<iostream.h>
#include<conio.h>
#include<stdlib.h>

void create(); // For creating a graph
void dfs(); // For Deapth First Search(DFS) Traversal.
void bfs(); // For Breadth First Search(BFS) Traversal.

struct node // Structure for elements in the graph
{
int data,status;
struct node *next;
struct link *adj;
};

struct link // Structure for adjacency list
{
struct node *next;
struct link *adj;
};

struct node *start,*p,*q;
struct link *l,*k;

int main()
{
int choice;
clrscr();
create();
while(1)
{
cout<<"-----------------------\n\n";
cout<<"1: DFS\n\n2: BSF\n\n3: Exit\n\nEnter
your choice: \n";
cin>>choice;
switch(choice)
{
case 1:
dfs();
break;
case 2:
bfs();
break;
case 3:
exit(0);
break;
default:
cout<<"Incorrect choice!Re-enter your
choice.";
getch();
}
}
return 0;
}

void create() // Creating a graph
{
int dat,flag=0;
start=NULL;
cout<<"Enter the nodes in the graph(0 to end): ";
while(1)
{
cin>>dat;
if(dat==0)
break;
p=new node;
p->data=dat;
p->status=0;
p->next=NULL;
p->adj=NULL;
if(flag==0)
{
start=p;
q=p;
flag++;
}
else
{
q->next=p;
q=p;
}
}
p=start;
while(p!=NULL)
{
cout<<"Enter the links to "<<p->data<<" (0 to
end) : ";
flag=0;
while(1)
{
cin>>dat;
if(dat==0)
break;
k=new link;
k->adj=NULL;
if(flag==0)
{
p->adj=k;
l=k;
flag++;
}
else
{
l->adj=k;
l=k;
}
q=start;
while(q!=NULL)
{
if(q->data==dat)
k->next=q;
q=q->next;
}
}
p=p->next;
}
cout<<"-------------------------";
return;
}

// Deapth First Search(DFS) Traversal.
void bfs()
{
int qu[20],i=1,j=0;
p=start;
while(p!=NULL)
{
p->status=0;
p=p->next;
}
p=start;
qu[0]=p->data;
p->status=1;
while(1)
{
if(qu[j]==0)
break;
p=start;
while(p!=NULL)
{
if(p->data==qu[j])
break;
p=p->next;
}
k=p->adj;
while(k!=NULL)
{
q=k->next;
if(q->status==0)
{
qu[i]=q->data;
q->status=1;
qu[i+1]=0;
i++;
}
k=k->adj;
}
j++;
}
j=0;
cout<<"Breadth First Search Results";
cout<<"---------------------------";
while(qu[j]!=0)
{
cout<<qu[j]<<" ";
j++;
}
getch();
return;
}

// Breadth First Search(BFS) Traversal.
void dfs()
{
int stack[25],top=1;
cout<<"Deapth First Search Results";
cout<<"---------------------------";
p=start;
while(p!=NULL)
{
p->status=0;
p=p->next;
}
p=start;
stack[0]=0;
stack[top]=p->data;
p->status=1;
while(1)
{
if(stack[top]==0)
break;
p=start;
while(p!=NULL)
{
if(p->data==stack[top])
break;
p=p->next;
}
cout<<stack[top]<<" ";
top--;
k=p->adj;
while(k!=NULL)
{
q=k->next;
if(q->status==0)
{
top++;
stack[top]=q->data;
q->status=1;
}
k=k->adj;
}
}
getch();
return;
}