Copy Constructor Big 3 C++ issue

问题:

I am struggling with implementing big 3 idea (assignment operator overload, copy constructor, destructor). my code below will crash the program. It compiles so I cannot even see any error hint. Please help.

enter code here

#include <iostream>
using namespace std;
#include <string>
#include <fstream>
#include <cmath>
#include <cstdlib>
#include <ctime>
#include <vector>
#include <windows.h>
#include <cstring>
#include <cctype>
#include <iomanip>
#include <algorithm>
#include<sstream>


class TwoD
{
private:
int MaxRows;
int MaxCols;
double** outerArray;

public:
TwoD(int maxRows, int maxCols)
{
    MaxRows = maxRows;
    MaxCols = maxCols;
    outerArray = new double *[MaxRows];
    for (int i = 0; i < MaxRows; i++)
        outerArray[i] = new double[MaxCols];
}

TwoD(const TwoD& rightside)
{
    for (int l = 0; l < MaxRows; l++)  
        for (int m = 0; m < MaxCols; m++)
            outerArray[l][m] = rightside.outerArray[l][m];    
}

void input()
{
    for (int k = 0; k < MaxRows; k++)
        for (int j = 0; j < MaxCols; j++)
            cin >> outerArray[k][j];
}

void outPut()
{
    for (int l = 0; l < MaxRows; l++)
    {
        for (int m = 0; m < MaxCols; m++)
            cout << outerArray[l][m] << " ";
        cout << endl;
    }
}

const TwoD& operator =(const TwoD& rightSide)
{
    for (int l = 0; l < MaxRows; l++)
    {
        for (int m = 0; m < MaxCols; m++)
            outerArray[l][m] = rightSide.outerArray[l][m];
        cout << endl;
    }

    return *this;
}



const TwoD operator + (const TwoD& rightSide)
{
    for (int l = 0; l < MaxRows; l++)
    {
        for (int m = 0; m < MaxCols; m++)
            outerArray[l][m] = outerArray[l][m] + rightSide.outerArray[l][m];
        cout << endl;
    }

    return *this;
}

~TwoD()
{
    for (int i = 0; i < MaxRows; i++)
        delete[] outerArray[i];
    delete[] outerArray;
}

};

int main()
{
TwoD example1(3, 3), example2(3,3), example3(3,3);
cout << "input example1" << endl;
example1.input();
example1.outPut();

cout << "input example2" << endl;
example2.input();
example2.outPut();

cout << "combining the two is" << endl;
example3 = example1 + example2;
example3.outPut();


return 0;
}

changed copy constructor

TwoD(const TwoD& rightside): MaxRows(rightside.MaxRows), MaxCols(rightside.MaxCols)
{
    outerArray = new double *[MaxRows];
    for (int i = 0; i < MaxRows; i++)
        outerArray[i] = new double[MaxCols];

    for (int l = 0; l < MaxRows; l++)  
        for (int m = 0; m < MaxCols; m++)
            outerArray[l][m] = rightside.outerArray[l][m];    
}

回答1:

1. Your copy constructor fails to allocate memory for the matrix.
2. Your copy assignment operator and operator+() fail to account for the possibility that *this and rightSide have different dimensions.