在二叉搜索树中找到最大深度

#include<stdio.h>
#include<conio.h>
#include\"malloc.h\"

struct node
{
    int data;
    struct node* left;
    struct node* right;
};
int size(struct node* n)
{
    if(n==NULL)
       return 0;
    else
       return (size(n->left)+1+size(n->right));
}

int maxdepth(struct node* n)
{
    int ldepth,rdepth;
    if(n==NULL)
    {
       return 0;
    }
    else
    {
       ldepth=maxdepth(n->left);
       rdepth=maxdepth(n->right);
       if(ldepth>rdepth)
          return (ldepth+1);
       else
          return (rdepth+1);
    }
}

int lookup(struct node* node,int target)
{
    if(node==NULL)
       return 0;
    else if(target==node->data)
       return 1;
    else if(target<node->data)
       return(lookup(node->left,target));
    else
       return(lookup(node->right,target));
}

struct node* newnode(int data)
{
     struct node* newnod=(struct node*)malloc(sizeof(struct node));
     newnod->data=data;
     newnod->left=NULL;
     newnod->right=NULL;
     return newnod;
}

struct node* insert(struct node* root,int target)
{
    if(root==NULL)
        return(newnode(target));
    else if(target<=root->data)
        root->left=insert(root->left,target);
    else 
        root->right=insert(root->right,target);
    return root;
}

void main()
{
    int result,s,max;
    struct node* newnode=NULL;
    clrscr();
    newnode=insert(newnode,2);
    newnode=insert(newnode,3);
    newnode=insert(newnode,4);
    max=maxdepth(newnode);
    printf(\"maxdepth %d\\n\",max);
    s=size(newnode);
    result=lookup(newnode,3);
    printf(\"size %d\\n\",s);
    printf(\"%d\",result);
    getch();
}

maxdepth

maxdepth

int maxdepth(struct node* n)
{
    int ldepth,rdepth;
    if(n==NULL)
    {
        return 0;
    }
    else
    {
        ldepth=maxdepth(n->left);
        rdepth=maxdepth(n->right);
        if(ldepth>rdepth)
            return (ldepth);
        else
            return (rdepth);
    }
}

maxdepth