c++ - 运算符重载、奇段错误、类、C++

Question

我的导师给了我一个关于重载运算符的练习。他给了我不能更改的 int main() 函数。我应该编写函数等，以便代码可以工作。不幸的是我有段错误。我注意到如果

 TSeries series4=series1(2,4);
 cout << "Series4: " << series4 << endl;

行被评论它或多或少工作。我将非常感谢你的帮助。

#include <iostream>
class TSeries {
public:
    TSeries()
    {
        _size = 0;
        _capacity = 0;
        _tab = NULL;
    }


    TSeries(float *tab, const int size)
    {
        _tab = new float[size];
        for (int i = 0; i < size; i++) _tab[i] = tab[i];
        _size = size;
        _capacity = 0;
    }

    ~TSeries() { delete[] _tab; }

    TSeries & operator+=(float value) { return insert(value); }
    TSeries & operator,(float value) { return insert(value); }
    TSeries & operator+(const TSeries & s)
    {
        //  if(this->_size != s._size) std::cout<<"Size doesn't match!"<<std::endl;
        /*else
        {
        std::cout<<"whee";
        for(int i; i<this->_size;i++)
        {
        //this->_tab[i] += s._tab[i];
        std::cout<<"nothing";
        }
        return *this;
        }*/
        //std::cout<<"sth";
    }

    TSeries & operator()(int position1, int position2)
    {
        // return *this;
    }

    TSeries & insert(float k)
    {
        if (_size >= _capacity) Enlarge();
        _tab[_size++] = k;
        return *this;
    }
    friend std::ostream & operator<<(std::ostream & out, const TSeries & s);


private:
    int _size, _capacity;
    float *_tab, *_itr;
    static int _nr;

    void Enlarge()
    {
        _capacity = 2 * _capacity + 1;
        float *tmp = new float[_capacity];

        for (int i = 0; i < _size; ++i)
        {
            tmp[i] = _tab[i];
        }
        delete[] _tab;
        _tab = tmp;
    }
};

std::ostream & operator<<(std::ostream & out, const TSeries & s)
{
    int przedostatni = s._size - 1;
    out << "(";
    for (int i = 0; i < s._size; i++)
    {
        out << (int)s._tab[i];
        if (i != przedostatni)
            out << ",";
    }
    out << ")" << std::endl;
}

using namespace std;
int main(int argc, char **argv) {
    TSeries series1;
    series1 += 1., 2., 4., 2.;
    cout << "Series1: " << series1 << endl;

    const int size = 7;
    float tab[size] = { 3.,3.,3.,4.,5.,1.,0. };
    const TSeries series2(tab, size);
    cout << "Series2: " << series2 << endl << endl;


    TSeries series3 = series1 + series2;
    cout << "Series3: " << series3 << endl << endl;

    series1 += 1., 0., 3.;
    series3 = series1 + series2;
    cout << "           " << series1 << endl;
    cout << "          +" << series2 << endl;
    cout << "        ---------------------" << endl;
    cout << "Series3:   " << series3 << endl << endl;

    TSeries series4 = series1(2, 4);
    cout << "Series4: " << series4 << endl;

    return 0;
}

/* output required:
Series1: (1,2,4,2)
Series2: (3,3,3,4,5,1,0)

Size doesn't match!
Series3: ()

(1,2,4,2,1,0,3)
+(3,3,3,4,5,1,0)
---------------------
Series3:   (4,5,7,6,6,1,3)

Series4: (4,2)
*/

Answer 1

1. std::ostream & operator<<(std::ostream & out, const TSeries & s)不返回任何东西。请加一个return out在函数结束时
2. operator()和 operator+都应该以 return *this 结尾
3. 正如 Devolus 已经指出的:您没有复制构造函数，也没有 operator=(const TSeries&)定义
4. 您可以使用 memcpy更快地复制数组。#
5. i在 operator+(const TSeries&) 的 for 循环中未初始化。
6. 你的 operator(int, int)当前确实改变了原始对象。这似乎不对。

代码:

#include <iostream>
class TSeries {
public:
    TSeries()
    {
        _size = 0;
        _capacity = 0;

        _tab = NULL;
    }


    TSeries(float *tab, const int size)
    {
        _size = size;
        _capacity = 0;

        _tab = new float[size];
        memcpy(_tab, tab, _size*sizeof(float));
    }

    TSeries(const TSeries& other)
    {
        _size = other._size;
        _capacity = other._capacity;

        _tab = new float[_size];
        memcpy(_tab, other._tab, _size*sizeof(float));
    }

    ~TSeries() 
    { 
        delete[] _tab;
    }

    TSeries & operator+=(float value) { return insert(value); }
    TSeries & operator,(float value) { return insert(value); }
    TSeries & operator+(const TSeries & other)
    {
        if (this->_size != other._size)
        {
            std::cout << "Size doesn't match!" << std::endl;
        }
        else
        {
            //std::cout << "whee";
            for (int i = 0; i < this->_size; i++)
            {
                _tab[i] += other._tab[i];
                //std::cout << "nothing";
            }
        }
        //std::cout<<"sth";
        return *this;
    }

    TSeries& operator=(const TSeries& other)
    {
        _size = other._size;
        _capacity = other._capacity;
        //Create tmp in case of self-assignment
        float *tmp = new float[_capacity];
        memcpy(tmp, other._tab, _size*sizeof(float));
        delete[] _tab;
        _tab = tmp;
        return *this;
    }

    TSeries operator()(int position1, int position2)
    {
        //TODO: Range-Check
        return TSeries(_tab + position1, position2 - position1);
    }

    TSeries & insert(float k)
    {
        if (_size >= _capacity) Enlarge();
        _tab[_size++] = k;
        return *this;
    }
    friend std::ostream & operator<<(std::ostream & out, const TSeries & s);


private:
    int _size, _capacity;
    float *_tab, *_itr;
    static int _nr;

    void Enlarge()
    {
        _capacity = 2 * _capacity + 1;
        float *tmp = new float[_capacity];
        memcpy(tmp, _tab, _size*sizeof(float));
        delete[] _tab;
        _tab = tmp;
    }
};

std::ostream & operator<<(std::ostream & out, const TSeries & s)
{
    int przedostatni = s._size - 1;
    out << "(";
    for (int i = 0; i < s._size; i++)
    {
        out << (int)s._tab[i];
        if (i != przedostatni)
            out << ",";
    }
    out << ")" << std::endl;
    return out;
}

using namespace std;
int main(int argc, char **argv) {
    TSeries series1;
    series1 += 1., 2., 4., 2.;
    cout << "Series1: " << series1 << endl;

    const int size = 7;
    float tab[size] = { 3.,3.,3.,4.,5.,1.,0. };
    const TSeries series2(tab, size);
    cout << "Series2: " << series2 << endl << endl;


    TSeries series3 = series1 + series2;
    cout << "Series3: " << series3 << endl << endl;

    series1 += 1., 0., 3.;
    series3 = series1 + series2;
    cout << "           " << series1 << endl;
    cout << "          +" << series2 << endl;
    cout << "        ---------------------" << endl;
    cout << "Series3:   " << series3 << endl << endl;

    TSeries series4 = series1(2, 4);
    cout << "Series4: " << series4 << endl;

    return 0;
}

/* output required:
Series1: (1,2,4,2)
Series2: (3,3,3,4,5,1,0)

Size doesn't match!
Series3: ()

(1,2,4,2,1,0,3)
+(3,3,3,4,5,1,0)
---------------------
Series3:   (4,5,7,6,6,1,3)

Series4: (4,2)
*/

输出

Series1: (1,2,4,2)

Series2: (3,3,3,4,5,1,0)


Size doesn't match!
Series3: (1,2,4,2)


           (4,5,7,6,6,1,3)

          +(3,3,3,4,5,1,0)

        ---------------------
Series3:   (4,5,7,6,6,1,3)


Series4: (7,6)

更新:

你的 operator+(const TSeries &)应该看起来像这样:

TSeries operator+(const TSeries & other)
{
    if (this->_size != other._size)
    {
        std::cout << "Size doesn't match!" << std::endl;
        return TSeries(); //Return empty object
    }
    TSeries tmp(*this); //Create copy
    for (int i = 0; i < tmp._size; i++)
    {
        tmp._tab[i] += other._tab[i];
    }
    return tmp;
}

还有你的operator()(int, int)像这样:

TSeries operator()(int position1, int position2)
{
    if (position1 < 0) position1 = 0;
    else if (position1 >= _size) position1 = _size - 1;

    if (position2 < position1) position2 = position1;
    else if (position2 >= _size) position2 = _size - 1;

    return TSeries(_tab + position1, position2 - position1);
}

也许您想在错误情况下抛出异常？