Print cousins of a given node in a tree?

Question

Print cousins of a given node (Not sibling) ??

Comments

What is the meaning of cousins???

---

Two nodes who are at the same level but does not have same parent are called cousins.

Answer 1

Step1 : Find the level of the node and parent of the node.
Step 2 : Pass the level and parent. Traverse the tree and print the node if it is at the level passed and does not have same parent.

using namespace std; 

struct node{ 
    struct node* left; 
    struct node* right; 
    int data; 
}; 

void inorder(struct node* root,int present_level,int level,struct node* parent) 
{ 
  if(root!=NULL) 
  { 
   if(parent!=root) 
       inorder(root->left,present_level+1,level,parent); 
   if(level==present_level) 
       cout<<root->data<<" "; 
   if(parent!=root) 
       inorder(root->right,present_level+1,level,parent); 
  } 
} 

void make_tree(struct node **root,int data) 
{ 
    if((*root)==NULL) 
    { 
        (*root)=new node; 
        (*root)->left=NULL; 
        (*root)->right=NULL; 
        (*root)->data=data; 
        return; 
    } 
    else 
    { 
        if (((*root)->data)< data)
            make_tree(&((*root)->right),data); 
        else 
            make_tree(&((*root)->left),data); 
    } 


} 

struct node* find_level_and_parent(struct node* root,int data,int* level) 
{ 
    struct node* parent=NULL; 
    struct node* child=root; 

    while(1) 
    { 
        if(child==NULL) 
            return NULL; 
        if(child->data==data) 
        { 
            return parent; 
        } 
        if(data>child->data) 
        { 
            parent=child; 
            child=child->right; 
            *level=*level+1; 
        } 
        else if(data<=child->data) 
        { 
            parent=child; 
            child=child->left; 
            *level=*level+1; 
        } 
    } 
} 

int main() 
{ 
    struct node* root=NULL; 
    make_tree(&root,6); 
    make_tree(&root,8); 
    make_tree(&root,3); 
    make_tree(&root,4); 
    make_tree(&root,44); 
    make_tree(&root,34); 
    make_tree(&root,12); 
    make_tree(&root,9); 
    make_tree(&root,2); 
    make_tree(&root,1); 
    make_tree(&root,33); 

    print_tree(root);

    int level=0; 
    struct node* temp=find_level_and_parent(root,44,&level); 
    if(temp!=NULL) 
    { 
        inorder(root,0,level,temp);
        return 0; 
    } 
    return 1; 
}

Tested code and is working fine.