C++ HW - 定义类 - 头文件中有其他类问题对象的对象(超出范围？)，(也重新定义运算符，读入读出)

Question

这是我第一次使用大部分代码。在下面的这个 instancepool.h 文件中，我收到错误消息，提示我不能使用 vector(第 14 行)或将 instance& 作为返回类型(第 20 行)。尽管我已经包含了它们，但它似乎无法使用实例对象。

#ifndef _INSTANCEPOOL_H
#define _INSTANCEPOOL_H
#include "instance.h"
#include <iostream>
#include <string>
#include <vector>
#include <stdlib.h>
using namespace std;

class InstancePool 
      {
      private:
              unsigned instances;//total number of instance objects
              vector<instance> ipp;//the collection of instance objects, held in a vector
      public:
             InstancePool();//Default constructor. Creates an InstancePool object that contains no Instance objects
             InstancePool(const InstancePool& original);//Copy constructor. After copying, changes to original should not affect the copy that was created.
             ~InstancePool();//Destructor
             unsigned getNumberOfInstances() const;//Returns the number of Instance objects the the InstancePool contains.
             const instance& operator[](unsigned index) const;
             InstancePool& operator=(const InstancePool& right);//Overloading the assignment operator for InstancePool.
             friend istream& operator>>(istream& in, InstancePool& ip);//Overloading of the >> operator. 
             friend ostream& operator<<(ostream& out, const InstancePool& ip);//Overloading of the << operator. 
      };
#endif

这是实例.h:

#ifndef _INSTANCE_H
#define _INSTANCE_H
///////////////////////////////#include "instancepool.h"
#include <iostream>
#include <string>
#include <stdlib.h>
using namespace std;

class Instance 
{
      private:
              string filenamee;
              bool categoryy;
              unsigned featuress;

              unsigned* featureIDD;
              unsigned* frequencyy;
              string* featuree;

      public:
             Instance (unsigned features = 0);//default constructor
             unsigned getNumberOfFeatures() const; //Returns the number of the keywords that the calling Instance object can store.
             Instance(const Instance& original);//Copy constructor. After copying, changes to the original should not affect the copy that was created.
             ~Instance() { delete []featureIDD; delete []frequencyy; delete []featuree;}//Destructor.
             void setCategory(bool category){categoryy = category;}//Sets the category of the message. Spam messages are represented with true and and legit messages with false.//easy
             bool getCategory() const;//Returns the category of the message.
             void setFileName(const string& filename){filenamee = filename;}//Stores the name of the file (i.e. “spam/spamsga1.txt”, like in 1st assignment) in which the message was initially stored.//const string& trick?
             string getFileName() const;//Returns the name of the file in which the message was initially stored.
             void setFeature(unsigned i, const string& feature, unsigned featureID,unsigned frequency) {//i for array positions
                  featuree[i] = feature;
                  featureIDD[i] = featureID;
                  frequencyy[i] = frequency;
                  }
             string getFeature(unsigned i) const;//Returns the keyword which is located in the ith position.//const string
             unsigned getFeatureID(unsigned i) const;//Returns the code of the keyword which is located in the ith position.
             unsigned getFrequency(unsigned i) const;//Returns the frequency
             Instance& operator=(const Instance& right);//Overloading of the assignment operator for Instance.
             friend ostream& operator<<(ostream& out, const Instance& inst);//Overloading of the << operator for Instance.
             friend istream& operator>>(istream& in, Instance& inst);//Overloading of the >> operator for Instance. 


};
#endif

此外，如果它有帮助，这里是 instance.cpp:

// Here we implement the functions of the class apart from the inline ones

#include "instance.h"
#include <iostream>
#include <string>
#include <stdlib.h>
using namespace std;

      Instance::Instance(unsigned features) {  //Constructor that can be used as the default constructor.
               featuress = features;
               if (features == 0)
                   return;
               featuree = new string[featuress]; // Dynamic memory allocation.
               featureIDD = new unsigned[featuress];
               frequencyy = new unsigned[featuress];  
               return;
               }

      unsigned Instance::getNumberOfFeatures() const {//Returns the number of the keywords that the calling Instance object can store.
               return featuress;}

      Instance::Instance(const Instance& original) {//Copy constructor.
              filenamee = original.filenamee;
              categoryy = original.categoryy;
              featuress = original.featuress;

              featuree = new string[featuress]; 
              for(unsigned i = 0; i < featuress; i++) {
                           featuree[i] = original.featuree[i];
                           }
              featureIDD = new unsigned[featuress];
              for(unsigned i = 0; i < featuress; i++) {
                           featureIDD[i] = original.featureIDD[i];
                           }
              frequencyy = new unsigned[featuress]; 
              for(unsigned i = 0; i < featuress; i++) {
                           frequencyy[i] = original.frequencyy[i];} 
              }

      bool Instance::getCategory() const { //Returns the category of the message.
               return categoryy;}

      string Instance::getFileName() const { //Returns the name of the file in which the message was initially stored.
             return filenamee;}

      string Instance::getFeature(unsigned i) const { //Returns the keyword which is located in the ith position.//const string
             return featuree[i];}

      unsigned Instance::getFeatureID(unsigned i) const { //Returns the code of the keyword which is located in the ith position.
               return featureIDD[i];}

      unsigned Instance::getFrequency(unsigned i) const { //Returns the frequency
               return frequencyy[i];}

      Instance& Instance::operator=(const Instance& right) { //Overloading of the assignment operator for Instance. 
                if(this == &right) return *this;
                delete []featureIDD;
                delete []frequencyy;
                delete []featuree;
                filenamee = right.filenamee;
                categoryy = right.categoryy;
                featuress = right.featuress;
                featureIDD = new unsigned[featuress];
                frequencyy = new unsigned[featuress];
                featuree = new string[featuress];
                for(unsigned i = 0; i < featuress; i++) {
                             featureIDD[i] = right.featureIDD[i]; }
                for(unsigned i = 0; i < featuress; i++) {
                             frequencyy[i] = right.frequencyy[i]; }
                for(unsigned i = 0; i < featuress; i++) {
                             featuree[i] = right.featuree[i]; }
                return *this;
                }

      ostream& operator<<(ostream& out, const Instance& inst) {//Overloading of the << operator for Instance. 
               out << endl << "<message file=" << '"' << inst.filenamee << '"' << " category=";
               if  (inst.categoryy == 0)
                   out << '"' << "legit" << '"';
               else
                   out << '"' << "spam" << '"';
               out << " features=" << '"' << inst.featuress << '"' << ">" <<endl;
               for (int i = 0; i < inst.featuress; i++) {
                   out << "<feature id=" << '"' << inst.featureIDD[i] << '"' << " freq=" << '"' << inst.frequencyy[i] << '"' << "> " << inst.featuree[i] << " </feature>"<< endl;
                   }
               out << "</message>" << endl;
               return out;
               }

      istream& operator>>(istream& in, Instance& inst) { //Overloading of the >> operator for Instance.
               string word;
               string numbers = "";
               string filenamee2 = "";
               bool categoryy2 = 0;
               unsigned featuress2;
               string featuree2;
               unsigned featureIDD2;
               unsigned frequencyy2;
               unsigned i;
               unsigned y;
               while(in >> word) {
                    if (word == "<message") {//if at beginning of message
                       in >> word;//grab filename word
                       for (y=6; word[y]!='"'; y++) {//pull out filename from between quotes
                           filenamee2 += word[y];} 
                       in >> word;//grab category word
                       if (word[10] == 's')
                          categoryy2 = 1;
                       in >> word;//grab features word
                       for (y=10; word[y]!='"'; y++) {
                           numbers += word[y];} 
                       featuress2 = atoi(numbers.c_str());//convert string of numbers to integer
                       Instance tempp2(featuress2);//make a temporary Instance object to hold values read in
                       tempp2.setFileName(filenamee2);//set temp object to filename read in
                       tempp2.setCategory(categoryy2);
                       for (i=0; i<featuress2; i++) {//loop reading in feature reports for message
                           in >> word >> word >> word;//skip two words
                           numbers = "";//reset numbers string
                           for (int y=4; word[y]!='"'; y++) {//grab feature ID
                               numbers += word[y];} 
                           featureIDD2 = atoi(numbers.c_str());
                           in >> word;//
                           numbers = "";
                           for (int y=6; word[y]!='"'; y++) {//grab frequency
                               numbers += word[y];} 
                           frequencyy2 = atoi(numbers.c_str());
                           in >> word;//grab actual feature string
                           featuree2 = word;
                           tempp2.setFeature(i, featuree2, featureIDD2, frequencyy2);
                           }//all done reading in and setting features
                       in >> word;//read in last part of message : </message>
                       inst = tempp2;//set inst (reference) to tempp2 (tempp2 will be destroyed at end of function call)
                       return in;
                       }
                    }
               }

和instancepool.cpp:

// Here we implement the functions of the class apart from the inline ones

#include "instancepool.h"
#include "instance.h"
#include <iostream>
#include <string>
#include <vector>
#include <stdlib.h>
using namespace std;

      InstancePool::InstancePool()//Default constructor. Creates an InstancePool object that contains no Instance objects
            {
            instances = 0;
            ipp.clear();                      
            }

      InstancePool::~InstancePool() {
            ipp.clear();}

      InstancePool::InstancePool(const InstancePool& original) {//Copy constructor. 
            instances = original.instances;
            for (int i = 0; i<instances; i++) {
                ipp.push_back(original.ipp[i]);
                }
            }

      unsigned InstancePool::getNumberOfInstances() const {//Returns the number of Instance objects the the InstancePool contains.
            return instances;}

      const Instance& InstancePool::operator[](unsigned index) const {//Overloading of the [] operator for InstancePool.
            return ipp[index];}

      InstancePool& InstancePool::operator=(const InstancePool& right) {//Overloading the assignment operator for InstancePool.
            if(this == &right) return *this;
                ipp.clear();
                instances = right.instances;
                for(unsigned i = 0; i < instances; i++) {
                             ipp.push_back(right.ipp[i]); }
                return *this;
                }

      istream& operator>>(istream& in, InstancePool& ip) {//Overloading of the >> operator. 
            ip.ipp.clear();
            string word;
            string numbers;
            int total;//int to hold total number of messages in collection
            while(in >> word) {
                     if (word == "<messagecollection"){
                              in >> word;//reads in total number of all messages
                              for (int y=10; word[y]!='"'; y++){
                                  numbers = "";
                                  numbers += word[y];
                                  }
                              total = atoi(numbers.c_str());
                              for (int x = 0; x<total; x++) {//do loop for each message in collection
                                  in >> ip.ipp[x];//use instance friend function and [] operator to fill in values and create Instance objects and read them intot he vector
                                  }
                              }
                     }           
            } 

      ostream& operator<<(ostream& out, const InstancePool& ip) {//Overloading of the << operator. 
            out << "<messagecollection messages=" << '"' << '>' << ip.instances << '"'<< endl << endl;
            for (int z=0; z<ip.instances; z++) {
                out << ip[z];}
            out << endl<<"</messagecollection>\n";
            }

这段代码目前也没有正确地写入文件，至少我敢肯定它有很多问题。我希望我的帖子不会太多，如果有任何帮助，我们将不胜感激。谢谢!

Answer 1

您创建了一个 Instance 类型，但正在尝试使用 instance。案例很重要。