Question

我向大家介绍我正在为大学课程编写课程的所有课程。我还有一些方法可以完全达到我的任务要求，但是我已经得到了程序的基本草案，没有错误（据说）并且它似乎运行...但是它突然把我踢进了Xcode的调试器并给出了我：

Thread 1: EXC_BAD_ACCESS(code=2, address=0x7fff95c1e5f5)

这是命令行输出，直到它踢出去：

    -----------------------
    Quarterly_sales_taxator
    -----------------------


    How many company divisions will we be dealing with?  2


    Am I correct in assuming that there are 4 sales quarters?    yes



    Please enter the sales Company Division #1 brought in for Sales Quarter #1   20
    (lldb)

这是我的代码：

    //
    //  quarterly_sales_taxator.cpp
    //  Ch. 7 program #7
    //
    //  Created by John Doe on 11/27/12.
    //

    #include <iostream>
    #include <iomanip>
    #include <string>
    #include <sstream>
    #include <cctype>
    using namespace std;

    void read_company_divisions_and_sales_quarters(double **, int, int);
        //void write_company_divisions_and_sales_quarters_to_array(double **, int, int);    // This will be used later on to read data from a file.
    void display_quarterly_sales_array(double **, int, int);

    string temp;    // A global temporary placeholder variable; I use this several times.


    int main()
    {
        int COMPANY_DIVISIONS,
            SALES_QUARTERS = 4;

        double **quarterly_sales_form;


        cout << "\n\n-----------------------\nQuarterly_sales_taxator\n-----------------------\n\n";

        cout << "\nHow many company divisions will we be dealing with?  ";
        getline(cin, temp);
        stringstream(temp)>>COMPANY_DIVISIONS;

        while (COMPANY_DIVISIONS < 1 || isdigit(COMPANY_DIVISIONS == false))
        {
            cout << "\n\n------"
                 << "\nError:"
                 << "\n------"
                 << "\n\nYou have entered an invalid choice."
                 << "\nPlease type a number greater than zero.    ";

            getline(cin, temp);
            stringstream(temp)>>COMPANY_DIVISIONS;
        }

        cout << "\n\nAm I correct in assuming that there are 4 sales quarters?    ";
        getline(cin, temp);

                // Convert to uppercase.
            for (int count = 0; count < temp.length(); count ++)
            {
                temp[count] = toupper(temp[count]);
            }

            if (temp == "NO" || temp == "NOPE" || temp == "INCORRECT" || temp == "YOU ARE NOT" || temp == "YOU ARE INCORRECT" || temp == "NEGATIVE" || temp == "NEGATORY")
            {
                cout << "\nOk, then how many sales quarters are we dealing with?    ";
                getline(cin, temp);
                stringstream(temp)>>SALES_QUARTERS;
            }

        cout << endl << endl;

            // This sets up the 2d array.
        quarterly_sales_form = new double *[COMPANY_DIVISIONS];
        for (int count = 0; count < COMPANY_DIVISIONS; count ++)
        {   quarterly_sales_form[COMPANY_DIVISIONS] = new double [SALES_QUARTERS];  }

        read_company_divisions_and_sales_quarters(quarterly_sales_form, COMPANY_DIVISIONS, SALES_QUARTERS);
            //  write_company_divisions_and_sales_quarters_to_array(quarterly_sales_form, COMPANY_DIVISIONS, SALES_QUARTERS);   // I'll add this feature later.


        cout << "\n\nHere's what you entered:\n\n";
        display_quarterly_sales_array(quarterly_sales_form, COMPANY_DIVISIONS, SALES_QUARTERS);

            // Since we used a series of pointers, we need to free the allocated space back up.
        for (int count = 0; count < COMPANY_DIVISIONS; count ++)
        {   delete[] quarterly_sales_form[COMPANY_DIVISIONS];  }
        delete[] quarterly_sales_form;



        return 0;
    }


    /*############################################
     # read_company_divisions_and_sales_quarters #
     ############################################*/
    void read_company_divisions_and_sales_quarters(double **array, int DIVISIONS, int QUARTERS)
    {

            for (int count = 0; count < QUARTERS; count++)
            {

                for (int index = 0; index < DIVISIONS; index++)
                {
                    cout << "\nPlease enter the sales Company Division #" << count+1 << " brought in for Sales Quarter #" << index+1 << "   ";
                    getline(cin, temp);
                    stringstream(temp) >> array[count][index];
                }
            }
    }


    /*################################
     # display_quarterly_sales_array #
     #################################*/
    void display_quarterly_sales_array(double **array, int DIVISIONS, int QUARTERS)
    {
        for (int count = 0; count < DIVISIONS; count++)
        {
            cout << "\nCompany division #" << count+1 << ":\n";
            for (int index = 0; index < QUARTERS; index++)
            {    cout << array[count][index] << ", ";    }
        }

    }

有些灵魂请告诉我我做错了什么？

Answer 1

    {   quarterly_sales_form[COMPANY_DIVISIONS] = new double [SALES_QUARTERS];  }

在此行中，COMPANY_DIVISIONS应为count。

Answer 2

除了Dan Hulme所说的，似乎这一行

stringstream(temp) >> array[count][index];

应该是

std::istringstream(temp) >> std::skipws >> array[index][count];

除了使用std::istringstream而不是std::stringstream并且确保左手边有一个左手边，在类型读取变得更有趣之前并不严格需要，这也会使索引反转：{ {1}}在index和COMPANY_DIVISIONS之上运行count。

真正的问题当然是：谁分发了这样的作业？指针操作和分配最好留给低级库编写者。这是C ++而不是C：我们可以而且应该使用抽象。让这段代码异常安全是一项重大挑战，教会人们如何编写破碎的代码（例如异常不安全代码）毫无意义。

对于一个似乎应该正常运行的程序，我得到了一个奇怪的错误。＆＃34;

2 个答案: