如何在模板 class 中构建 operator==

Question

我有一个任务，我想使用这些规范构建模板。

ISet是一个容器，它保存了某个值，其中顺序无关紧要并且不允许重复（或倍数）。动态分配的 T 类型数组应该用作 Set 的内部数据结构。 Set 应该继承自下面的 ISet 接口 - 这个不能修改:

template <typename T>
class ISet
{
public:
virtual bool insert (T element) = 0;
virtual bool remove (T element) = 0;
virtual int size () const = 0;
};

• insert (T element): adds elements to the set and returns true provided that
the element is not already present in the quantity (in which case the element is not added and false is returned).

• remove (T element): removes elements from the set and returns true.
If the element is missing in the quantity, false returns.

• size (): returns the number of elements in the set.
In addition to the member functions, you must implement constructor, destructor, copy constructor
and assignment operator.

到目前为止我想出了这个代码：

#pragma once
#include <string>
#include <iostream>

using namespace std;

template <class T>
class ISet
{

public:

    virtual bool insert(T element) = 0;
    virtual bool remove(T element) = 0;
    virtual int size() const = 0;
};


#pragma once
#include "ISet.h"

template <class T>
class Set : public ISet<T>
{
public:
    Set(string name);
    ~Set();
    Set(const Set &origin);
    //Set& operator=(const Set &origin);

    bool insert(T element);
    bool remove(T element);
    int size()const;

private:
    string name;
    T *arr;
    int cap, nrOfElement;
};



template<class T>
Set<T>::Set(string name)
{
    this->name = name;
    this->cap = 10;
    this->nrOfElement = 0;
    this->arr = new T[this->cap];

}

template<class T>
Set<T>::~Set()
{
    delete[] arr;
}

template<class T>
Set<T>::Set(const Set & origin)
{
    this->nrOfElement = origin.nrOfElement;
    this->cap = origin.cap;

    arr = new T*[cap];

    for (int i = 0; i < nrOfElement; i++)
    {
        arr[i] = origin.arr[i];
    }

}

template<class T>
bool Set<T>::insert(T element)
{
    bool found = false;

    if (nrOfElement == 0)
    {
        this->arr[0] = element;
        this->nrOfElement++;
    }
    else
    {
        for (int i = 0; i < this->nrOfElement; i++)
        {
            if (this->arr[i] == element)
            {
                i = this->nrOfElement;
                found = true;
            }
        }
        if (found == false)
        {
            this->arr[nrOfElement++] = element;
        }
    }

    return found;
}

template<class T>
bool Set<T>::remove(T element)
{
    bool removed = false;

    for (int i = 0; i < this->nrOfElement; i++)
    {
        if (this->arr[i] == element)
        {
            this->arr[i] = this->arr[nrOfElement];
            nrOfElement--;
            removed = true;
        }
    }
    return removed;
}

template<class T>
int Set<T>::size() const
{
    return this->nrOfElement;
}

当我开始通过添加我们假设用来测试模板的不同数据类型来测试此代码时，我的问题就开始了。

#include "Set.h"
#include "ISet.h"
#include "Runner.h"

int main()
{
    _CrtSetDbgFlag(_CRTDBG_ALLOC_MEM_DF | _CRTDBG_LEAK_CHECK_DF);
    Set<string> test("test");
    test.insert("lol");
    cout << test.size();
    test.remove("lol");
    cout << test.size();

    Set<Runner> test2("test");


    getchar();
    return 0;
}

收到错误消息“未找到采用左手操作数类型 'Runner' 的运算符。所以我必须创建一个运算符==来处理这个但我不知道？跑步者 class 看起来像这样：

#pragma once
#include "Competitor.h"
#include <string>

using namespace std;

class Runner : public Competitor
{
public:
    Runner();
    Runner(string firstName, string lastName, int startNr);
    ~Runner();

    void addResult(int resultTime);
    int getResult() const;
    string toString() const;
    Runner *clone() const;

private:
    int resultTime;

};

#include "Runner.h"

Runner::Runner()
{
    this->resultTime = 0;
}

Runner::Runner(string firstName, string lastName, int startNr) : Competitor(firstName, lastName, startNr)
{
    this->resultTime = 0;
}


Runner::~Runner()
{
}

void Runner::addResult(int resultTime)
{
    this->resultTime = resultTime;
}

int Runner::getResult() const
{
    return this->resultTime;
}

string Runner::toString() const
{
    return (to_string(this->resultTime) + " sec");
}

Runner * Runner::clone() const
{
    return new Runner(*this);
}

如何构建适用于此的运算符==？

Answer 1

您需要将 operator== 添加到 Runner class:

bool operator==(const Runner& other) const;

如何在模板 class 中构建 operator==

How to build a operator== in template class

c++

templates

abstract-class

virtual-functions

operators