Rename Error

Hello,

I am currently Trying to rename a file to a randomly created string. Every time a file is passed to my program i want it to be renamed to a very random name always ending in '.dl'. However i am experience some difficulty's. When i pass a file to the program the file disappears totally.

Thank You For Any Help.

Here is the program:

Code:

#include <iostream>
#include <windows.h>

#include <cstdio>

char Random_Char;
char Altered_Filename[16];

using namespace std;

void Get_Random_Char()
{	
	Random_Char = (rand()%62);

	if(Random_Char <= 25) 
	{	
	   Random_Char += 97;	
	}
	else if(Random_Char >= 26 && Random_Char <= 51) 
	{   
	   Random_Char += 39;
	}
	else if(Random_Char >= 52) 
	{		 
	   Random_Char -= 4;	
	}
}

void Rename_The_File()
{
	 int Chars_In_Name = 0;
	 
	 srand(time(0));
	 
	 do{
		 
	 Get_Random_Char();

	 Altered_Filename[Chars_In_Name] = Random_Char;
		
	 Chars_In_Name++;

	 }while (Chars_In_Name != 13);
	
	 Altered_Filename[13] = '.';
	 Altered_Filename[14] = 'd';
	 Altered_Filename[15] = 'l';
	 Altered_Filename[16] = '\0';
}

int main(int argc, char *argv[])
{
	Rename_The_File();
	
	cout << argv[1] <<"\n\n";
	cout << Altered_Filename <<"\n\n";
	
	system("pause");
	
	if (rename(argv[1], Altered_Filename) != 0)
	{
	   cout << "ERROR!!!\n\n";
	}
	else
	{
	   cout << "Sucess!!!\n\n";
	}
	
	system("pause");
}

The output is:

Code:

C:\Documents and Settings\Chris\Desktop\New Text Document.txt

hYtMPRRtUNAHA.dl

Press any key to continue . . .
Sucess!!!

Press any key to continue . . .

(New Text Document.txt Is no longer on desktop nor is there a file called hYtMPRRtUNAHA.dl)

Code:

char Random_Char;
char Altered_Filename[16];

Avoid global variables - use arguments.

Code:

	if(Random_Char <= 25) 
	{	
	   Random_Char += 97;	
	}
	else if(Random_Char >= 26 && Random_Char <= 51) 
	{   
	   Random_Char += 39;
	}
	else if(Random_Char >= 52) 
	{		 
	   Random_Char -= 4;	
	}

Confusing. Try using chars instead - if Random_Char <= 'a') for example.

Code:

	 do{
		 
	 Get_Random_Char();

	 Altered_Filename[Chars_In_Name] = Random_Char;
		
	 Chars_In_Name++;

	 }while (Chars_In_Name != 13);

Indent properly.

Code:

	 Altered_Filename[13] = '.';
	 Altered_Filename[14] = 'd';
	 Altered_Filename[15] = 'l';
	 Altered_Filename[16] = '\0';

Preferably, use std::string or strcat.

Code:

	if (rename(argv[1], Altered_Filename) != 0)

As you can see, the argument is the full path to the file, but your renamed filename isn't. The behavior is actually defined, but you're overlooking it.
See rename for more information. Specify full path or switch current directory to the directory where your file to be renamed is.

Try not to mix spaces and tabs. Use only tabs or only spaces for indentation. I recommend tabs.

I don't believe you that the file is being deleted, assuming it even existed to begin with. What do you actually think that code is doing?

And furthermore, why do you think that?

I think Elysia is right, you should be preserving the path (eg. "C:\Documents and Settings\Chris\Desktop\") and just append a random name to the path.

You should probably also check if the file exists before trying to rename it. Sure it's extremely unlikely to exist, but it's those long shots that create the hard to find bugs.

To preface this, I'm not really a C++ programmer. I prefer the C approach, but here C++ strings should be used for simplicity.

Code:

#include <iostream>
#include <string>
#include <cstdlib>

void getRandomName(std::string &szRename);

void getRandomName(std::string &szRename)
{
	char *szAlphabet = "abcdefghijklmnopqrstuvwxyz";

	szRename.erase();
	for(int i=0;i<20;i++)
	{
		szRename += szAlphabet[rand() &#37; (strlen(szAlphabet)-1)];
	}
	szRename += ".dl";
}

int main(int argc, char *argv[])
{
	std::string szPath, szRename, szFull;
	size_t i;
	
	srand(time(NULL));
	
	if(argc < 2)
	{
		std::cout << "Usage: " << argv[0] << " <file>" << std::endl;
		return 1;
	}
	szPath = argv[1];
	getRandomName(szRename);
	i = szPath.find_last_of('\\');	// Note: \\ is Windows based.
	if(i != std::string::npos)
	{
		szFull = szPath.substr(0, i+1);
		szFull = szFull + szRename;
	}
	else szFull = szRename;
	std::cout << "szFull = " << szFull << std::endl;
	if(rename(argv[1], szFull.c_str()) != 0)
	{
		std::cout << "Error:  Unable to rename file." << std::endl;
		return 2;
	}
	std::cout << "Renamed from \"" << szPath << "\" to \"" << szFull << "\"." << std::endl;
	return 0;
}

If you notice, most of the code is error checking. It handles strings that have backslashes and those that don't. It doesn't currently handle forward slashes, however, but since the OP included Windows.h, I had assumed a Windows platform.

Apologies for any errors. This hasn't really been checked.

Also, apologies for my earlier post. I didn't read the code thoroughly enough.

Thank you very much to all

Thanks MacGyver
That code works now i just have to learn what it all is!!!