Thread: Help to copy files in c++

> system("copy input.c_str() output.c_str()")
There's no magic substitution of "do what I mean" going on here.

You need to build the command line yourself, eg.

Code:

string cmd = "copy ";
cmd += input;
// and so on
system( cmd.c_str() );

The code as you have it now will execute the shell command "copy input.c_str() output.c_str()". Unless you have a file called "input.c_str()", that won't get you very far.

You need to build a proper command string by concatenation, then pass that to system().

Better yet, don't use system at all. Use CopyFile from windows.h. (The copy command is windows-specific, so you don't lose portability.)

You look the function up in the help and find out why two arguments aren't enough. What else? How much clearer can an error message be than, "too few arguments"?

And you still think that code gets executed inside string literals.

Originally Posted by CornedBee

Better yet, don't use system at all. Use CopyFile from windows.h. (The copy command is windows-specific, so you don't lose portability.)

Actually, I would write my own CopyFile() function that abstracts away the underlying OS and gives a standard interface no matter what OS you're on. That way, when you port to another OS, all you need to do is add another #ifdef block of code in your own CopyFile() function:

Code:

bool Filesys::CopyFile( const char*  src, const char*  dest, bool  overWrite )
{
#ifdef  WIN32
    // Put your Windows specific code here.
#elif defined( LINUX )
    // Put Linux specific code here.
...
#endif
}

No, if I wanted portability, I'd just use Boost.Filesystem.

Originally Posted by cpjust

Actually, I would write my own CopyFile() function that abstracts away the underlying OS and gives a standard interface no matter what OS you're on. That way, when you port to another OS, all you need to do is add another #ifdef block of code in your own CopyFile() function:

Too much for a newbie, I would say.

Code:

CopyFile(InputString.c_str(), string(OutputString+InputFileNameString).c_str(), TRUE); // true if you want it to fail if it already exists.

This should work better.

Remember to include <windows.h>

Originally Posted by Elysia

Too much for a newbie, I would say.

True, but something to keep in mind for later on down the road.

You need a different string, for just the output filename.

Code:

string Input = "C:\\bla.txt";
string CopiedFile = "bla.txt";
string OutputFolder = "C:\\test\\";

CopyFile(Input.c_str(), string(OutputFolder+CopiedFile).c_str(), TRUE);

And you can use "cin >> OutputFolder" type thing to get user input about the folder. (You don't have to type "\\" in that case, one slash is enough I believe.

Just don't use this code in something that has internet access, someone can use your code to copy files into your system.

Originally Posted by execute

And you can use "cin >> OutputFolder" type thing to get user input about the folder. (You don't have to type "\\" in that case, one slash is enough I believe.

What a user types is stored inside a buffer. A double "\\" is only required when coding a \ into code since the \ character is treated as an escape character.

Just don't use this code in something that has internet access, someone can use your code to copy files into your system.

Say what?

Like dont make a program, that connects using sockets to the internet, and reads internet data or data provided by other people. An example would be, don't use it as an instant messenger for example.

If you don't understand don't worry about it, I'm sure you won't use it in the way i described anyway.