Thread: Using strcpy from const char*

Hello there,

I must admit, I'm TERRIBLE with filetypes. I remember the earlier days, where if I had a char to char* error or something similar, I'd just throw * or & operators in and hope something would work. Well, I'm not much better now.

My problem is this : I'm using #define to define a value of text ( a filename ), and I want the program to check for this. If it ISN'T declared, it'll ask the user for input. Code goes like this :

Code:

//////// PRINT INPUT TO FILE
void Encryptor::printinputfile()
{
     #ifdef OUTFILENAME
     strcpy(filename.c_str(), OUTFILENAME);  // Where filename is a string
     
     #else
     cout << "\nFilename >> ";
     cin >> filename;
     cout << endl;
     #endif
     
     fout.open(filename.c_str(), ios::binary);
     fout << input;
     fout.close();
}

I'm getting "invalid conversion from const char* to char*" on the line that calls strcpy.

So, is there a better / more intelligent way to do this ? Also, how would I solve this problem above ?

Thanks very much,
Quentin

Mario, I've tried that, but because filename is a string (not char or array) it gives me "no matching function for call to strcpy(...)"
Thanks though

Salem, thanks, that works. However, is there a better way to do this than using a #define ?

You should write your function to work either way without the use of the #define. Perhaps have it take a filename as a string parameter and default it to an empty string(). If the filename is empty, ask the user. You can then control the use of the default filename higher up in the code.

If you want your option to be controlled by a preprocessor symbol, then just make a symbol that is either defined or not defined, and let that choose between passing a string to the printinputfile function or not. However, you could just use code to do that, perhaps by getting the option from the command line or somewhere else.