问题描述
我正在尝试使用进程创建一个二叉树。
-module(binarytree).
-export([start/1,loop/2]).
start(N) ->
P = spawn(?MODULE,loop,[N,self(),self()]),P ! create_nodes,receive
end.
loop(0,_,_) ->
done;
loop(N,Root,LeftNode,RightNode) ->
receive
create_nodes ->
MyPid = self(),LeftNode = spawn(?MODULE,[N-1,MyPid,???,???]),RightNode = spawn(?MODULE,LeftNode ! create_nodes,RightNode ! create_nodes;
_ ->
ok
end,loop(N,RightNode).
没有 LeftNode
和 RightNode
我成功创建树结构,但我想将 LeftNode
和 RightNode
保存在循环状态。创建节点时应该传入什么函数参数?
更新: 感谢 Nalin Ranjan。更改这些行:
MyPid = self(),RightNode ! create_nodes;
致:
MyPid = self(),NewLeftNode = spawn(?MODULE,"",""]),NewRightNode = spawn(?MODULE,NewLeftNode ! create_nodes,NewRightNode ! create_nodes,NewLeftNode,NewRightNode);
解决方法
loop(N,Root,LeftNode,RightNode) ->
receive
create_nodes ->
MyPid = self(),NewLeftNode = spawn(?MODULE,loop,[N-1,MyPid,"empty-child-node","empty-child-node"),NewRightNode = spawn(?MODULE,"empty-child-node"]),NewLeftNode ! create_nodes,NewRightNode ! create_nodes,loop(N,NewLeftNode,NewRightNode);
_ -> ok
end,RightNode).
试试这个。