用c++读写多个文件

read write multiple files in c++

本文关键字：文件 读写 c++      更新时间：2023-10-16

我想从用户那里获得多个文件地址，然后在struct.txt文件和其他程序导出文件中以二进制模式读取和写入它们。请引导我。导入-合并导出-取消合并

#include <iostream>
#include <string>
#include <fstream>
#include <iterator>
#include <algorithm>
using namespace std;
int tedad_file=0; // get count of files from user //
int main()
{
    int tr=0;
    cout << "please enter count of files you want to merge ";
    cin >>  tedad_file;
    cout << "n";
    std::string *files[tedad_file];
    int counter=0;
    int temp=0;
    for(;temp<tedad_file;temp++) // getting file's address from user and add them into arrays of string (files variable)
    {
        cout << "Lotfan address file " << temp + 1 << " vared konid: n";
        cin >> *files[temp];
    }
    std::ofstream output_file( "D:\struct.txt", std::ios::binary ) ;
    int x=0;
    for(;x<tedad_file;x++) // for - read content of files to merge them into struct.txt ---- for example tedad_file is 3
    {
        std::ifstream first_file((char *)&files[tedad_file], std::ios::binary ) ;
        output_file << first_file.rdbuf();
    }
    return 0;
}

您应该使用std::vector<std::string> files和files.push_back(filename)例如：

int main()
{
    std::vector<std::string> files;
    cout << "please enter count of files you want to merge ";
    int file_count = 0;
    cin >> file_count;
    for (int temp = 0; temp<file_count; temp++)
    {
        cout << "Lotfan address file " << " vared konid: n";
        std::string filename;
        cin >> filename;
        files.push_back(filename);
    }
    std::ofstream output_file("D:\struct.txt", std::ios::binary);
    for (auto file : files)
    {
        std::ifstream fin(file, std::ios::binary);
        output_file << fin.rdbuf();
    }
    return 0;
}

否则，请使用new运算符。但new方法容易出错。例如：

int main()
{
    cout << "please enter count of files you want to merge ";
    int tedad_file = 0; 
    cin >> tedad_file;
    cout << "n";
    std::string *files = new std::string[tedad_file];
    for (int temp = 0; temp<tedad_file; temp++) 
    {
        cout << "Lotfan address file " << " vared konid: n";
        cin >> files[temp];
    }
    std::ofstream output_file("D:\struct.txt", std::ios::binary);
    for (int temp = 0; temp<tedad_file; temp++)
    {
        std::ifstream first_file(files[temp], std::ios::binary);
        output_file << first_file.rdbuf();
    }
    delete[]files;
    return 0;
}

为什么要写这行：std::string *files[tedad_file];？你必须先为这个指针分配内存。如果你不在这里使用指针，而是做一些类似于std::string files[tedad_file]的事情，那会更好。您的代码没有为数组中的字符串分配内存，这就是出现segfault的原因。

通过这种方式解决

int tedad_file=0; // Daryaft tedad file jahate edgham //
int main()
{
int tr=0;
cout << "Lotfan Tedad file jahate edgham vared konid: ";
cin >>  tedad_file;
cout << "n";
std::string files[tedad_file];
int counter=0;
int temp=0;
for(;temp<tedad_file;temp++)
{
cout << "Lotfan address file " << temp + 1 << " vared konid: n";
cin >> files[temp];
}
streampos size1;
std::ofstream output_file( "D:\test.txt", std::ios::binary ) ;
int x=0;
string dd;
for(;x<tedad_file;x++)
{
dd = files[x];
std::ifstream first_file(dd.c_str(), std::ios::binary ) ;
output_file << first_file.rdbuf();
size1 = first_file.tellg();
cout << size1;
}
return 0;
}
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