Question

我正在尝试将学生记录的数据保存到文本文件和二进制文件中，但输出不允许我输入任何数据，我找不到问题所在。有人可以帮忙吗？

我打开了一个文本文件和一个二进制文件，我使用了函数。视觉工作室13没有向我显示任何错误。

    #include <iostream> 
    #include <fstream>
    #include <string>

    struct dof { int DD, MM, YYYY; };

    struct record
    {
        string firstname;
        string lastname;
        string adress;
        string highschooldegree;
        int phonenumber;
        int ID;
        int group;
        int coursescore[5];
        char grade;
        float GPA;
        dof birthday;
    }student;

void getdata(ifstream &, record &student);
void getdatabin(ifstream &, record &student);
void outputdata(ofstream &, record &student);
void outputdatabin(ofstream &, record &student);

int main()
{
    record student;
    ifstream infile;
    ifstream infilebin;
    ofstream outfile;
    ofstream outfilebin;

    infile.open("student.txt", ios::in | ios::app);
    if (infile.good())
        getdata(infile, student);
    else
        cout << "File cant be opened " << endl;
    infile.close();

    outfile.open("student.txt", ios::out);
    if (outfile.good())
        outputdata(outfile, student);
    else
        cout << "File cant be opened " << endl;
    outfile.close();

    infilebin.open("student.bin", ios::binary | ios::in | ios::app);
    if (infilebin.good())
        getdatabin(infilebin, student);
    else
        cout << "File cant be opened " << endl;
    infilebin.close();

    outfilebin.open("student.bin", ios::binary | ios::out);
    if (outfilebin.good())
        outputdatabin(outfilebin, student);
    else
        cout << "File cant be opened " << endl;
    outfilebin.close();

    return 0;
}

void getdata(ifstream &infile, record &student)
{
    for (int i = 0; i < 3; i++)
    {
        infile >> student.firstname;
        infile >> student.lastname;
        infile >> student.adress;
        infile >> student.highschooldegree;
        infile >> student.phonenumber;
        infile >> student.ID;
        infile >> student.group;
        for (int j = 0; j < 3; j++)
        {
            infile >> student.coursescore[j];
        }
        infile >> student.grade;
        infile >> student.GPA;
        infile >> student.birthday.DD >> student.birthday.MM >> student.birthday.YYYY;
    }
}

void getdatabin(ifstream &infilebin, record &student)
{
    infilebin.read(reinterpret_cast<char *>(&student), sizeof(student));
}

void outputdata(ofstream &outfile, record &student)
{
    outfile << student.firstname;
    outfile << student.lastname;
    outfile << student.adress;
    outfile << student.highschooldegree;
    outfile << student.phonenumber;
    outfile << student.ID;
    outfile << student.group;
    for (int j = 0; j < 3; j++)
    {
        outfile << student.coursescore[j];
    }
    outfile << student.grade;
    outfile << student.GPA;
    outfile << student.birthday.DD << student.birthday.MM << student.birthday.YYYY;
}

void outputdatabin(ofstream &outfilebin, record &student)
{
    outfilebin.write(reinterpret_cast<char *>(&student), sizeof(student));
}

Answer 1

我认为您不能使用以下方式将结构写入文件：

outfilebin.write(reinterpret_cast<char *>(&student), sizeof(student));

它会写一些指针而不是字符串值;

另外，当你做

时

outfile << student.firstname;
outfile << student.lastname;

它将输出所有这些字符串而没有分隔符，例如＆＃34; firstnamelastname15 ...＆＃34;你怎么期望读回来？

要将值写入二进制文件，请使用大小合适的结构，如

struct student {
  char firstname[40];
  char lastname[40];
  int age;
}

您可以将整个结构读/写为二进制文件。

要将值写入文本文件，请使用分隔符或固定宽度：

fout << student.firstname << "\t" << student.lastname << "\t" << student.age << "\t" << std::endl;

要读取它们，请按行读取并将它们解析为结构（您可以在此处使用结构中的std字符串）。

学生的记录

1 个答案: