【发布时间】：2016-03-18 01:00:57
【问题描述】：
我想知道如何在 BoxClass 类的链接列表中调用 toString() 方法。 BoxClass 有一个 double length、width 和 height。
我的 BoxClass：
class BoxClass{
private:
double length;
double width;
double height;
public:
// Default constructor w/ no parameters
BoxClass(){
length = 0;
width = 0;
height = 0;
}
// Constructor with arguments
BoxClass(double boxLength, double boxWidth, double boxHeight){
length = boxLength;
width = boxWidth;
height = boxHeight;
}
// Setters and Getters
void setLength(double boxLength){
length = boxLength;
}
double getLength(){
return length;
}
void setWidth(double boxWidth){
width = boxWidth;
}
double getWidth(){
return width;
}
void setHeight(double boxHeight){
height = boxHeight;
}
double getHeight(){
return height;
}
// Returns the volume of the boxes
double Volume(){
return (length * width * height);
}
// toString method for boxes, returns "(length) x (width) x (height) string
string toString(){
return ("(" + to_string(length)+ "x" + to_string(width) + "x" + to_string(height) + ")");
}
}; // End of BoxClass() class
LinkNode.h
//Template ListNode class definition.
#ifndef LINKNODE_H
#define LINKNODE_H
template <typename T> class LinkList;
template <typename T> class LinkNode{
friend class LinkNode <T>;
public:
LinkNode(const T &);
T getData()const;
T data;
LinkNode <T> *nextPtr;
};
template <typename T> LinkNode <T>::LinkNode(const T &info):data(info), nextPtr(NULL){
// Empty body
}
template <typename T>T LinkNode<T>::getData()const{
return data;
}
#endif
Main（创建类，将其添加到链接列表
// Create the Box class
BoxClass userBox(length, width, height);
// Add box class to Link List
Box.insertNode(userBox);
Box.print();
LinkList.h print() 方法
template<typename T>void LinkList<T>::print()const {
// To list off nodes
int counter = 1;
if (isEmpty()) {
cout << "No boxes in list!\n";
} else {
LinkNode<T>*currentPtr = firstPtr;
cout << "Your boxes in increasing order of volume is:\n";
// while (currentPtr) {
while (currentPtr != NULL) {
// Output as "#. (length x width x height)
cout << counter << ". " << currentPtr->data << endl;
printf(" %i. %.2f\n", counter, currentPtr->data);
currentPtr = currentPtr->nextPtr;
counter++;
}
}
}
LinkList.h
//Template LinkList class definition.
#ifndef LINKLIST_H
#define LINKLIST_H
#include <iostream>
#include "LinkNode.h"
using namespace std;
template<typename T> class LinkList {
public:
LinkList();
void addNode(const T &);
void insertNode(const T &);
bool isEmpty() const;
void print() const;
private:
LinkNode<T>*firstPtr;
LinkNode<T>*getNewNode(const T &);
};
template<typename T>LinkList<T>::LinkList() :firstPtr(NULL) {
// Empty body
}
template <typename T>void LinkList<T>::insertNode(const T &value) {
LinkNode<T>*newPtr = getNewNode(value);
bool inserted = false;
if (isEmpty() || (newPtr->data < firstPtr->data)) {
newPtr->nextPtr = firstPtr;
firstPtr = newPtr;
// cout << " " << newPtr->data << " inserted at front of list.\n";
printf(" %.2f inserted at front of list.\n", newPtr->data);
} else {
LinkNode<T>*currentPtr = firstPtr;
while (currentPtr->nextPtr && !inserted) {
if (newPtr->data < currentPtr->nextPtr->data) {
// cout << " " << newPtr->data << " inserted before " << currentPtr->nextPtr->data << ". " << endl;
printf(" %.2f inserted before %.2f.\n", newPtr->data, currentPtr->nextPtr->data);
newPtr->nextPtr = currentPtr->nextPtr;
currentPtr->nextPtr = newPtr;
inserted = true;
} else {
currentPtr = currentPtr->nextPtr;
}
}
if (!inserted) {
currentPtr->nextPtr = newPtr;
printf(" %.2f inserted at the end of list.\n", newPtr->data);
}
}
}
template<typename T>bool LinkList<T>::isEmpty()const {
return firstPtr == NULL;
}
template<typename T>LinkNode<T>*LinkList<T>::getNewNode(const T &value) {
return new LinkNode<T>(value);
}
template<typename T>void LinkList<T>::print()const {
// To list off nodes
int counter = 1;
if (isEmpty()) {
cout << "No boxes in list!\n";
} else {
LinkNode<T>*currentPtr = firstPtr;
cout << "Your boxes in increasing order of volume is:\n";
// while (currentPtr) {
while (currentPtr != NULL) {
// Output as "#. (length x width x height)
cout << counter << ". " << currentPtr->data << endl;
printf(" %i. %.2f\n", counter, currentPtr->data);
currentPtr = currentPtr->nextPtr;
counter++;
}
}
}
#endif
我的问题是——我该如何遍历列表并调用toString() BoxClass 方法？我尝试了cout << data.toString() << endl; 中的所有内容，但这不起作用。这几天一直卡在这个问题上，谁能帮帮我？
编辑：添加 LinkList.h
【问题讨论】：
-
基本上，您的实现缺少
iterator的概念。从链表外部，我应该能够说“给我第一个节点”，然后“给我下一个节点”并循环。是的，您现在可以在内部在 列表中执行此操作，但在公开场合，无法执行此操作。所以这就是你需要实现的。