Question

我写了一个程序，为一个结构数组动态分配内存。它看起来工作正常，但是当我尝试删除阵列时，计算机会制作一个＆＃34; bong＆＃34;噪音和程序停止响应。它不会抛出错误或任何东西，只是停止。我尝试了delete和delete[]，结果相同。我已经尝试移动删除位置，发现我可以在创建后立即将其删除，但不能在将其传递给任何函数后删除。谁能告诉我为什么我不能删除记忆？

#include <iostream>
#include <iomanip>
#include <fstream>
using std::cin;
using std::cout;
using std::endl;
using std::ifstream;
using std::ofstream;
using std::setw;
using std::left;
using std::fixed;
using std::setprecision;

//structure of an employee
struct Employee
{
    char first_name[32];
    char last_name[32];
    char SSN[11];
    float wage;
    int hours;
    char status;
};

void ReadData(Employee work_force[]);
void PrintData(Employee work_force[], int number_entries);
float CalculateStarightPay(Employee worker);
float CalculateOvertimePay(Employee worker);
int FindNumberEntries();

const int SPACING = 15;                             //spacing used in formating
const char dataFile[] = "EmployeeData.txt";         //file to read data from
const int union_dues = 5;                           //amount deducted from pay for the union

int main()
{
    int number_entries = FindNumberEntries();
    //array of employees
    Employee * work_force = new Employee[number_entries];

    //read in data
    ReadData(work_force);

    //prints the data
    PrintData(work_force, number_entries);

    //clean up memory
    delete[] work_force;

    return 0;
}

//finds the number of entries in the file
int FindNumberEntries()
{
    int counter = 0;
    //worker to read through file entries
    Employee worker_temp;

    ifstream input;

    input.open(dataFile);

    if (input.is_open())
    {
        while (!input.eof())
        {
            input >>
                worker_temp.first_name >>
                worker_temp.last_name >>
                worker_temp.SSN >>
                worker_temp.wage >>
                worker_temp.hours >>
                worker_temp.status;

            cin.clear();

            counter++;
        }

        input.close();
    }
    else
    {
        cout << "File could not be opened!" << endl;
    }

        return counter - 1;
}

//reads employee data from file
void ReadData(Employee work_force[])
{
    ifstream input;

    input.open(dataFile);

    //reads in entries
    if (input.is_open())
    {
        for (int i = 0; !input.eof(); i++)
        {
            //reads in employee data
            input >>
                work_force[i].first_name >>
                work_force[i].last_name >>
                work_force[i].SSN >>
                work_force[i].wage >>
                work_force[i].hours >>
                work_force[i].status;

            cin.clear();
        }

        input.close();
    }
    else
    {
        //error that file could not open
        cout << "File could not be opened!" << endl;
    }

}

//calculates straight pay
float CalculateStarightPay(Employee worker)
{
    //determines of worker is fulltime or not
    if (worker.status == 'F')
    {
        if (worker.hours > 40)
        {
            return ((worker.wage * 40) - 5);
        }
        else
        {
            return (worker.wage * worker.hours) - union_dues;
        }
    }
    else
    {
        if (worker.hours > 40)
        {
            return (worker.wage * 40);
        }
        else
        {
            return worker.wage * worker.hours;
        }
    }
}

//calculate overtime pay
float CalculateOvertimePay(Employee worker)
{
    //deermines if there are any overtime hours
    if (worker.hours <= 40)
    {
        return 0;
    }
    else
    {
        //calculates overtime pay
        return ((worker.hours - 40) * (worker.wage * 1.5));
    }
}

//prints employee data in a well formated manner
void PrintData(Employee work_force[], int number_entries)
{
    delete work_force;
    float straight_pay = 0.0F;
    float Overtime_pay = 0.0F;
    char name[32] = { '\0' };

    //print headers
    cout << left <<
        setw(SPACING) << "Name" <<
        setw(SPACING) << "SSN" <<
        setw(SPACING) << "Hourly Wage" <<
        setw(SPACING) << "Hours Worked" <<
        setw(SPACING) << "Straight Pay" <<
        setw(SPACING) << "Overtime Pay" << 
        setw(SPACING) << "Status" << 
        setw(SPACING) << "Net Pay" << endl;

    //prints data for each EMPLOYEE
    for (int i = 0; i < number_entries; i++)
    {
        straight_pay = CalculateStarightPay(work_force[i]);
        Overtime_pay = CalculateOvertimePay(work_force[i]);
        //adds a space after first name
        work_force[i].first_name[strlen(work_force[i].first_name) + 1] = '\0';
        work_force[i].first_name[strlen(work_force[i].first_name)] = ' ';
        //puts last name and first name together
        strcpy(name, strcat(work_force[i].first_name, work_force[i].last_name));

        //prints out all the data in a nic eformat
        cout << fixed << setprecision(2) <<
            setw(SPACING ) << name <<
            setw(SPACING) << work_force[i].SSN << '$' <<
            setw(SPACING) << work_force[i].wage <<
            setw(SPACING) << work_force[i].hours << '$' <<
            setw(SPACING) << straight_pay << '$' <<
            setw(SPACING) << Overtime_pay <<
            setw(SPACING) << work_force[i].status << '$' <<
            setw(SPACING) << (straight_pay + Overtime_pay) << endl;
    }
}

Answer 1

请delete work_force;位于PrintData的顶部。
使用std::string s作为您的姓名和SSN。（固定长度的字符串是等待发生的可用性事故）。
使用std::vector<Employee>。重要的是，这意味着您不再需要使用new（这是您应该总是尝试避免的事情）。这也意味着您只需要阅读一次文件 - 您只需阅读该条目，然后使用push_back将其推送到向量。

从输入流中读取时，您需要尝试读取，然后测试流以查看是否已经点击了eof。所以read函数看起来像：

    while (input >>
         worker_temp.first_name >>
         worker_temp.last_name >>
         worker_temp.SSN >>
         worker_temp.wage >>
         worker_temp.hours >>
         worker_temp.status)
    {
         workforce.push_back(worker_temp);
    }

删除动态数组C ++时程序崩溃

1 个答案: