创建三元组，实现三元组的基本操作，数据结构的表示用类型定义（typedef）描述，数据元素类型约定为ElemType,使用时可自行定义该数据类型。-Create a triple to achieve triple the basic operations, data structures that use type definitions (typedef) descr iption of the type of data elements agreed to ElemType, use d