将c ++类转换为字节数组 [英] converting c++ class to a byte array

问题描述

可以通过使用ios :: binary

$ b将下面的Student类转换为二进制文件

  #include < fstream> 
 #include< iostream> 
 using namespace std; 
 
 class Student {
 public：
 char name [40]，address [120]，gender; 
 double age; 
 bool is_blabla; 
}; 
 
 int main（）{
 
学生一; 
 strcpy（one.name，Cancan Can）; 
 strcpy（one.address，example example exampla）; 
 one.gender ='M'; 
 one.age = 25; 
 one.is_blabla = true; 
 
 ofstream ofs（fifthgrade.ros，ios :: binary）; 
 ofs.write（（char *）& one，sizeof（one））; 
 
学生二; 
 ifstream ifs（fifthgrade.ros，ios :: binary）; 
 ifs.read（（char *）& two，sizeof（two））; 
 
 //检查数据是否正确
 cout<< 学生姓名：< two.name<< endl; 
 
 
 return 0; 
} 
  

该文件如下所示：

http://i.imgur.com/GfkheWs.png p>

那么在这种情况下，我怎么做同样的事情来转换类为一个字节（或说char *）数组？

编辑：但在这种情况下，让我们假设我有一个类有方法。你给出的答案告诉我编写我自己的位运算符来序列化一个复杂的类。你可以参考一个好的源代码教它如何做或一个小样本/示例吗？

Edit2：我必须避免使用额外的库，因为我可能反序列化在机器/编译器上的序列化代码，我无法导入大多数库（例如，我将尝试反序列化在nvcc编译代码上的代码）。

示例dummy类将是这样：

  class Student {
 public：
 char name [40] [120]性别; 
 double age; 
 bool is_blabla; 
 
 void set_values（int，int）; 
 int doubleage（）{return age * 2;} 
}; 
  

解决方案

只需使用 std： ：stringstream 而不是 std :: ofstream 。

c $ c> char * 使用 std :: stringstream :: str（）（这个返回的是一个 std :: string 使用 std :: string :: c_str（）检索 char * c>）。

It is possible to convert the following Student class to a binary file by writing it with ios::binary

#include <fstream>
#include <iostream>
using namespace std;

class Student{
    public:
        char name[40], address[120], gender;
        double age;
        bool is_blabla;
};

int main() {

    Student one;
    strcpy(one.name, "Cancan Can");
    strcpy(one.address, "example example exampla");
    one.gender = 'M';
    one.age = 25;
    one.is_blabla = true;

    ofstream ofs("fifthgrade.ros", ios::binary);
    ofs.write((char *)&one, sizeof(one));

    Student two;
    ifstream ifs("fifthgrade.ros", ios::binary);
    ifs.read((char *)&two, sizeof(two));

    // check if the data is OK
    cout << "Student Name: " << two.name << endl;


    return 0;
}

The file looks like as follows:

http://i.imgur.com/GfkheWs.png

So how can I do the same thing to convert the class to a byte (or say char*) array in this case?

Edit: But in this case, Let's say I have a class having methods. The answers you gave is telling me to write my own bitwise operators to serialize a complex class. Can you refer to a good source teaching how it can be done or a small sample/example for it?

Edit2: I have to avoid using extra libraries because I may deserialize the serialized code on a machine/compiler that I cannot import most of the libraries (for example I will try to deserialize the code on an nvcc compiled code).

Example dummy class would be like this:

class Student{
    public:
        char name[40], address[120], gender;
        double age;
        bool is_blabla;

        void set_values (int,int);
        int doubleage() {return age*2;}
};

解决方案

Just use a std::stringstream rather than std::ofstream.

Then, access the char* using std::stringstream::str() (This return's a std::string, on which you can retrieve a char* using std::string::c_str()).

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