fstream <unable to read memory>。无法打印列表中的所有项目

Question

我正在开发一个菜单驱动程序，让用户基本上可以跟踪他们的分配任务和截止日期。我的程序处理标题为 "tasks.txt" 的文本文件，用户有 3 个与文本文件交互的选项：输入新任务、显示文件中的所有任务或按课程查找任务。我的程序运行得比较好，只是它似乎无法与文件完全交互。

下面是我的 output/input 文件：tasks.txt

CS162;Finish Project 2;04/10/2015
CS162;Finish Project 3;04/20/2015
CS162;Finish Project 4;05/10/2015
CS162;Finish Project 5;05/20/2015

这是我的代码：

#define _CRT_SECURE_NO_WARNINGS
#include <cstring>
#include <fstream>
#include <iostream>

using namespace std;

//Global constants
const int CAP = 100;
const int MAXCHAR = 201; // Task description can be a max of 200 characters in case its a long description (ie: specific instructions)

//Task struct
struct Task
{
    char courseName[MAXCHAR];
    char taskDescrip[MAXCHAR];
    char dueDate[MAXCHAR];
};

//function prototypes
void openFile(ifstream &inFile);
void loadData(ifstream &inFile, Task tasks[], int &listSize);
void exeCommand(char option, Task tasks[], int &listSize);
void displayMenu();
char readOption();
void getUserTask(Task &tempTask);
void addUserTask(Task tasks[], int &listSize, Task tempTask);
void printTasks(Task tasks[], const int listSize);
void writeFile(ofstream &outFile, Task tasks[], const int listSize);


//Main function
int main()
{
    int listSize = 0; //keep track of list size
    ofstream outFile; //output file stream variable
    ifstream inFile; //input file stream variable
    Task tasks[CAP]; //array of tasks
    char option; // user menu input for option
    openFile(inFile); //open up tasks.txt
    loadData(inFile, tasks, listSize); //load the data while in file into the array of tasks
    do
    {
        displayMenu();
        option = readOption();
        exeCommand(option, tasks, listSize);
    } while (tolower(option) != 'q');
    return 0;
}

//open the file
void openFile(ifstream &inFile)
{
    inFile.open("tasks.txt");
    if (!inFile)
    {
        cout << "file not open" << endl;
        exit(0);
    }
}

//load the data from the file to the array
// parameters: 
void loadData(ifstream &inFile, Task tasks[], int &listSize)
{
    while (!inFile.eof())
    {
        inFile.get(tasks[listSize].courseName, MAXCHAR, ';');
        inFile.ignore(200, ';');
        inFile.get(tasks[listSize].taskDescrip, MAXCHAR, ';');
        inFile.ignore(200, ';');
        inFile.get(tasks[listSize].dueDate, MAXCHAR, ';');
        inFile.ignore(200, '\n');
        listSize++;
    }
    inFile.close();
}

void displayMenu()
{
    cout << "Welcome to TaskTracker v.1" << endl;
    cout << "(a) Add a task" << endl;
    cout << "(l) List all tasks" << endl;
    cout << "(f) Find any tasks by course" << endl;
    cout << "(q) Quit" << endl << endl;
}

char readOption()
{
    char option;
    cout << "Please make a selection: ";
    cin.get(option);
    cin.ignore(100, '\n');
    return option;
}

void exeCommand(char option, Task tasks[], int &listSize)
{
    Task tempTask;// created object tempTask
    switch (tolower(option))
    {
    case 'a':
        cout << "You chose to add a task!" << endl;
        getUserTask(tempTask);//used aVideo as a parameter for getVideo
        addUserTask(tasks, listSize, tempTask);//tempTask 
        cout << endl << endl;
        break;
    case 'l':
        cout << "You chose print tasks!" << endl;
        printTasks(tasks, listSize);
        cout << endl << endl;
        break;
    case 'f':
        cout << "You chose to find an item by course!"<< endl;

        cout << endl << endl;
        break;
    case 'q':
        return;
    default:
        cout << "Invalid input!" << endl;
    }
}

void getUserTask(Task &tempTask)
{
    cout << "Please enter the course name {less than 101 characters): ";
    cin.get(tempTask.courseName, MAXCHAR);//user enters the course name
    cin.ignore(100, '\n');//ignores the next 100 characters or until newline

    cout << "Please enter a brief description of your task (less than 101 characters): ";
    cin.get(tempTask.taskDescrip, MAXCHAR);//user enters the task description
    cin.ignore(100, '\n');//ignores the next 100 characters or until newline

    cout << "Please enter the due date of this task. (mm/dd/yyy): ";
    cin.get(tempTask.dueDate, MAXCHAR);//user enters the task description
    cin.ignore(100, '\n');

}

void addUserTask(Task tasks[], int &listSize, Task tempTask)
{
    tasks[listSize++] = tempTask;
}

//prints the task list
void printTasks(Task tasks[], const int listSize)
{
    for (int i = 0; i < listSize; i++)
    {
        cout << tasks[i].courseName << ';' << tasks[i].taskDescrip << ';' << tasks[i].dueDate << endl;
    }
}

//writes to file at the end of the program
void writeFile(ofstream &outFile, Task tasks[], const int listSize)
{
    outFile.open("tasks.txt");
    for (int i = 0; i < listSize; i++)
    {
        outFile << tasks[i].courseName << ';' << tasks[i].taskDescrip << ';' << tasks[i].dueDate << endl;
    }
    return;
}

以下是调试器的输出：

Welcome to TaskTracker v.1
(a) Add a task
(l) List all tasks
(f) Find any tasks by course
(q) Quit

Please make a selection: l
You chose print tasks!
CS162;Finish Project 2;04/10/2015
CS162
CS162;Finish Project4;05/10/2015
CS162

Welcome to TaskTracker v.1
(a) Add a task
(l) List all tasks
(f) Find any tasks by course
(q) Quit

我已经研究了几个小时的代码并在网上搜索类似案例，但我的 fstream 似乎能够读取和加载每一行的课程名称，但跳过了任务描述和截止日期每一项其他任务。有人可以给我指出正确的方向吗？

菜单的“添加”选项似乎可以将新的用户输入任务加载到缓冲区，但应该将缓冲区中的所有任务保存到输出文件的写入文件功能似乎也不起作用。

我会继续寻找解决方案，但非常感谢您的帮助！

Answer 1

您的输入处理有问题。我在这些方面提出了更多建议：

void loadData(ifstream &inFile, Task tasks[], int &listSize)
{
    while (inFile.get(tasks[listSize].courseName, MAXCHAR, ';') &&
        inFile.ignore(200, ';') &&
        inFile.get(tasks[listSize].taskDescrip, MAXCHAR, ';') &&
        inFile.ignore(200, ';') &&
        inFile.get(tasks[listSize].dueDate, MAXCHAR, '\n'))
    {
        inFile.ignore(200, '\n');
        listSize++;
    }
    inFile.close();
}

产生以下输出：

Welcome to TaskTracker v.1
(a) Add a task
(l) List all tasks
(f) Find any tasks by course
(q) Quit

Please make a selection: l
You chose print tasks!
CS162;Finish Project 2;04/10/2015
CS162;Finish Project 3;04/20/2015
CS162;Finish Project 4;05/10/2015
CS162;Finish Project 5;05/20/2015

简而言之，您对第三个字段的请求也以 ';' 结尾（它在您的示例行上 而不是 ）正在跳到下一行直到它找到请求的分隔符，因此包括中间换行符和下一行的第一个字段。当前行的其余部分与后续行一起被丢弃 ignore。

祝你好运。

fstream <unable to read memory>。无法打印列表中的所有项目

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