插入二叉搜索树

void insert(struct TreeNode* root,int val)
{
    if(root)
    {
        if(root->val>val)
        {
            if(root->left)insert(root->left,val);
            else{
                struct TreeNode* newnode=(struct TreeNode*)malloc(sizeof(struct TreeNode));
                newnode->val=val;
                root->left=newnode;
            }
        }else{
            if(root->right)insert(root->right,val);
            else{
                struct TreeNode* newnode=(struct TreeNode*)malloc(sizeof(struct TreeNode));
                newnode->val=val;
                root->right=newnode;
            }
        }
    }
}
struct TreeNode* insertToBST(struct TreeNode* root, int val ) {
    if(root==NULL){
        struct TreeNode* newnode=(struct TreeNode*)malloc(sizeof(struct TreeNode));
        newnode->val=val;
        root=newnode;
    }
    insert(root, val);
    return root;
}