abstract-data-type

问题 This is a follow up question of: In scala, how to make type class working for Aux pattern? Considering the following example: trait Base { type Out def v: Out } object Base { type Aux[T] = Base { type Out = T } type Lt[T] = Base { type Out <: T } class ForH() extends Base { final type Out = HNil override def v: Out = HNil } object ForH extends ForH } trait TypeClasses { class TypeClass[B] def summon[B](b: B)(implicit ev: TypeClass[B]): TypeClass[B] = ev } object T1 extends TypeClasses {

问题 Here is a simple example: trait Base { type Out def v: Out } object Base { type Aux[T] = Base { type Out = T } class ForH() extends Base { type Out = HNil override def v: Out = HNil } object ForH extends ForH } class TypeClass[B] trait TypeClassLevel1 { def summon[B](b: B)(implicit ev: TypeClass[B]): TypeClass[B] = ev } object TypeClass extends TypeClassLevel1 { implicit def t1: TypeClass[Base.Aux[HNil]] = new TypeClass[Base.Aux[HNil]] implicit def t2: TypeClass[Int] = new TypeClass[Int] } it

问题 This document says std::list is inefficient: std::list is an extremely inefficient class that is rarely useful. It performs a heap allocation for every element inserted into it, thus having an extremely high constant factor, particularly for small data types. Comment: that is to my surprise. std::list is a doubly linked list, so despite its inefficiency in element construction, it supports insert/delete in O(1) time complexity, but this feature is completely ignored in this quoted paragraph.

问题 I am new to Stack Overflow and am teaching myself C++, but am still quite a beginner. After completing a nice chunk of the book I am using (which may be considered out dated and/or not a great book) I decided to re-enforce some concepts by trying them on my own, referencing the book only if needed, but I appear to be stuck. The concepts I am trying to tackle are inheritance, polymorphism, abstract data types (ADT), and separating the code for my classes into header files (.h) and C++ file (

问题 I am new to Stack Overflow and am teaching myself C++, but am still quite a beginner. After completing a nice chunk of the book I am using (which may be considered out dated and/or not a great book) I decided to re-enforce some concepts by trying them on my own, referencing the book only if needed, but I appear to be stuck. The concepts I am trying to tackle are inheritance, polymorphism, abstract data types (ADT), and separating the code for my classes into header files (.h) and C++ file (

问题 data Type is a descriptor of a set of values that lack identity What does mean by Lack of identity here? 回答1: Referring to the UML DataType description on IBM's Help Center: A data type is similar to a class; however, instances of data type are identified only by their value. If two data types have the same value, the instances are considered identical. So this means, that you can't seperate these objects of this DataType by their identifier, because they don't have any. Only the current

问题 data Type is a descriptor of a set of values that lack identity What does mean by Lack of identity here? 回答1: Referring to the UML DataType description on IBM's Help Center: A data type is similar to a class; however, instances of data type are identified only by their value. If two data types have the same value, the instances are considered identical. So this means, that you can't seperate these objects of this DataType by their identifier, because they don't have any. Only the current

问题 I'm taking Data-Structure course and got a little confused about what is considered to be an ADT (Abstract Data Type) and what isn't (and if it isn't an ADT then it must be the implementation?). Specifically, I'm talking about Heap. I've read in Wikipedia that " heap is a specialized tree-based data structure" does that mean it is an ADT? if so, then I can't understand the following line, also from Wikipedia "The heap is one maximally efficient implementation of an abstract data type called a

问题 I'm trying to write a program that takes a word letter by letter in every node of a doubly linked list and then with a function I wrote it will check if the word is a palindrome. When I compile my code I'm having problems in the part of the code it takes the input, so I would like to know how I can do it. int main(){ char c; Llista * list; Dada head = {0, NULL, NULL}; printf("insertar palabra para comprobar si es palindromo"); while((c=getchar()) != '\n'){ InsertAtTail(c); } palindromo(list);

问题 I have a ADT as follows: sealed trait Tree[A] case object EmptyTree extends Tree[Nothing] case class Leaf[A](value: A) extends Tree[A] case class Node[A](op: Seq[A] => A, branches: Tree[A]*) extends Tree[A] When i try to build a function to randomly create Trees i get a problem with the EmptyTree, the type system does not let go through def create(acc: Tree[A], currentDepth: Int): Tree[A] = currentDepth match { case maxDepth => Leaf(terminalSet(r.nextInt(terminalSet.length))) case 0 => { val