二叉树的插入，递归遍历和深度节点数

#include<stdlib.h>
#include<stdio.h>

struct tree_el {
int val;
struct tree_el * right, * left;
};

typedef struct tree_el node;

void insert(node ** tree, node * item) {
if(!(*tree))
{
*tree = item;
return;
}
if(item->val<=(*tree)->val)
insert(&(*tree)->left, item);
else if(item->val>(*tree)->val)
insert(&(*tree)->right, item);
}

void InOrd(node * tree)
{
if(tree->left)
InOrd(tree->left);
printf("%d ",tree->val);
if(tree->right)
InOrd(tree->right);
}

void PreOrd(node *tree)
{
printf("%d ",tree->val);
if(tree->left)
PreOrd(tree->left);
if(tree->right)
PreOrd(tree->right);
}

void PostOrd(node *tree)
{
if(tree->left)
PostOrd(tree->left);
if(tree->right)
PostOrd(tree->right);
printf("%d ",tree->val);
}

int TreeDepth(node* tree)
{
// the depth of a empty tree is 0
if(!tree)
return 0;

// the depth of left sub-tree
int nLeft = TreeDepth(tree->left);
// the depth of right sub-tree
int nRight = TreeDepth(tree->right);

// depth is the binary tree
return (nLeft > nRight) ? (nLeft + 1) : (nRight + 1);
}

int BTreeNodeCount(node *tree)
{
if(tree == 0)
return 0;
else
{
int l = BTreeNodeCount(tree->left);
int r = BTreeNodeCount(tree->right);
return l + r + 1;
}
}

int main() {
node * curr, * root;
int i;
int data;
int lenth;

root = NULL;
printf("请输入要插入的元素,按Ctrl + Z结束输入\n");
while(scanf("%d",&data)!= EOF)
{
curr = (node *)malloc(sizeof(node));
curr->left = curr->right = NULL;
curr->val = data;
insert(&root, curr);
}
printf("先序遍历 : ");
PreOrd(root);

printf("\n中序遍历 : ");
InOrd(root);

printf("\n后序遍历 : ");
PostOrd(root);

printf("\n树的深度为 : %d\n", TreeDepth(root));

printf("树的节点数为：%d\n", BTreeNodeCount(root));

return 0;
}