每个C/C++程序员都应该知道的四个文件处理技巧

2021年3月16日13:00:17 发表评论 651 次浏览

我们将讨论以下列出的四个文件黑客：

重命名–使用C / C ++重命名文件
删除–使用C / C ++删除文件
文件大小–使用C / C ++获取文件大小
检查是否存在–检查C / C ++中是否存在文件

// A C++ Program to demonstrate the
// four file hacks every C/C++ must know
  
// Note that we are assuming that the files
// are present in the same file as the program
// before doing the below four hacks
#include<stdio.h>
#include<stdlib.h>
#include<stdbool.h>
  
// A Function to get the file size
unsigned long long int fileSize( const char *filename)
{
     // Open the file
     FILE *fh = fopen (filename, "rb" );
     fseek (fh, 0, SEEK_END);
     unsigned long long int size = ftell (fh);
     fclose (fh);
  
     return (size);
}
  
// A Function to check if the file exists or not
bool fileExists( const char * fname)
{
     FILE *file;
     if (file = fopen (fname, "r" ))
     {
         fclose (file);
         return ( true );
     }
     return ( false );
}
  
// Driver Program to test above functions
int main()
{
     printf ( "%llu Bytes\n" , fileSize( "Passwords.txt" ));
     printf ( "%llu Bytes\n" , fileSize( "Notes.docx" ));
  
     if (fileExists( "OldData.txt" ) == true )
         printf ( "The File exists\n" );
     else
         printf ( "The File doen't exist\n" );
  
     rename ( "Videos" , "English_Videos" );
     rename ( "Songs" , "English_Songs" );
  
     remove ( "OldData.txt" );
     remove ( "Notes.docx" );
  
     if (fileExists( "OldData.txt" ) == true )
         printf ( "The File exists\n" );
     else
         printf ( "The File doesn't exist\n" );
  
     return 0;
}

输出如下：