C++中类的封装写出一个文件加密的小项目

 文件的加密较为简单，当然也可以修改它的加密方式等，供大家参考

#include<string>
#include<fstream>
class ReaderFile
{
public:string Read(const string& filename){cout << "读取文件，获取明文"<<endl;std::ifstream ifile;//输入流对象std::string src;//明文，读取内容放入src中char ch;ifile.open(filename);if (!ifile.is_open()){cout << "文件不存在" << endl;return src;}while (!ifile.eof())//fstream / ifstream / ofstream 类中的 成员函数eof()用来检测是否到达文件尾，如果到达文件尾返回非0值，否则返回0{ifile.get(ch);//读取字符src += ch;}ifile.close();return src;}
};
class WriterFile
{
public:void Write(const string& filename, const string& ciphertext)//将密文写入文件中{cout << "保存密文，写入文件" << endl;ofstream ofile;ofile.open(filename);if (!ofile.is_open()){cout << "文件不存在" << endl;return;}for (auto ch : ciphertext)//范围for{ofile.put(ch);}ofile.close();}
};
class Encryptor
{
public:string Encrypt(const string& plaintext){cout << "数据加密，将明文转换为密文" << endl;std::string es;for (auto ch : plaintext){char c = ch;if (islower(c)){c = (c + 5) % 26 + 'a';//加密方法es += c;}}return es;}
};
//组合
class EncryptFacade//加密器
{
private:ReaderFile reader;Encryptor encrypt;WriterFile writer;public:EncryptFacade() {}void FileEncrypt(const string& des, const string& src)//把源文件加密写入目标文件{std::string s = reader.Read(src);if (s.empty()){cout << "加密失败!" << endl;return;}std::string e = encrypt.Encrypt(s);writer.Write(des, e);}
};void main()
{EncryptFacade ef;ef.FileEncrypt("des.txt", "src.txt");}