c++ - 一次写入多个文件

Question

我想在循环中创建多个文件并向其中写入一些内容。我做了以下代码。但它只创建一个名为“1”的文件而不是五个文件(从 1 到 5):

#include <fstream>
#include<iostream>
using namespace std;
int main(){
  FILE *fp;
  ofstream os;
  char i;
  char fileName[] = "0.txt";
  for(i='1';i<='5';i++)
  {
     fileName[0]=i;
     .
     os.open (fileName);
     os<<"Hello"<<"\n";
  }
}

代码有什么问题吗？我将如何获得这五个文件？

Answer 1

std::ofstream::open 的引用具体说明:

Open file Opens the file identified by argument filename, associating it with the stream object, so that input/output operations are performed on its content. Argument mode specifies the opening mode.

If the stream is already associated with a file (i.e., it is already open), calling this function fails.

您永远不会关闭您在循环中使用的文件，因此 open 第二次到第五次失败。

添加它:

  for(i='1';i<='5';i++)
  {
     fileName[0]=i;
     os.open (fileName);
     os<<"Hello"<<"\n";
     os.close();
  }

此外，您应该检查 open() 是否成功:

  for(i='1';i<='5';i++)
  {
     fileName[0]=i;
     os.open (fileName);
     if(os) // checks if open() succeeeded
     {
       os<<"Hello"<<"\n";
       os.close();
     }
  }