线性表的数据对象集合为 {a1,a2,....an}，每个元素的类型均为Datatype。其中，除第一个元素a1外，每一个元素有且 只有一个直接前驱元素，除了最后一个元素an外，每一个元素有且只有一个直接后继元素。数据元素之间的关系是一对一的 关系。-Linear tables set of data objects is {a1, a2, .... an}, the type of each element are Datatype. Among them, in addition to the first element a1, every element has one and only one direct precursor element, an element except the last one, every element has one and only one immediate successor element. The relationship between data elements is one to one relationship.