Data Structures using C++

  #include<iostream> 
  #include<stdlib.h> 
  using namespace std;
  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<<" 
      1: DFS 
      2: BSF 
      3: Exit 
      Enter your choice: "; 
       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; 
  }