linux C++ 读写文件

原创

wx6405b2c488d4e 2023-03-07 00:59:12 博主文章分类：c++ ©著作权

文章标签 #include linux ios 文章分类 JavaScript 前端开发

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从现在开始，进行linux的学习了，开始呢，总想着，windows下的C++已经很熟悉了，所以呢，linux'下的c编程，应该就很快上手，上来就不应该从0开始了，可渐渐发现，根本不是这样的，即使是一个简单的文件读写操作，也使用了很长时间，呵呵，眼高手低阿，不过，还是很有收获的，慢慢来吧，还有时间，学习！学习

恩就这样吧，

#include<cstring>
#include<unistd.h>
#include<errno.h>
#include<fcntl.h>
#include<iostream>
using namespace std;
int main()
{
   //open the file if not process exit and output the err message
   char* fileName="hehe.txt";
   int fileDes=open(fileName,O_CREAT|O_RDWR|O_APPEND,0666);// we need the file fcntl.h
   if(fileDes==-1)
   {
      cout<<"the file open failed with the code : "<<errno<<endl; //we need the errno.h
      return 0;
   }
   cout<<"the file open success\n";
   //first we need to read the file content and then output to the screen after that write the time
   int fileSize=lseek(fileDes,0,SEEK_END)+1;
   lseek(fileDes,0,fileSize);
    char buf[1024]={0};

   while(read(fileDes,buf,1024)>0)//read we need the file unistd.h
   {
      cout<<buf<<endl;
   }
   strcpy(buf,"\nthis is a other day\n");
   if(write(fileDes,buf,strlen(buf))==-1)// write we need the file unistd.h strlen need the file cstring
   {
      cout<<"write file error with the code :"<<errno<<endl; 
   }
   close(fileDes);//close we need the file unistd.h
}