stuck on loop for (infile.fail())

[mux77]

I am trying to get this code to get the user to correctly enter the ifstream file by using the if(infile.fail()) statement. it catches the failure, but when I tried to loop it back to have the user try again it gets stuck in an infinite loop. here are a couple of my options I have tried. one I just exit the program, and have to manually restart it, but that is inefficient (it works though). The other catches the failulure but then I can't get it not to get caught in an infinite loop.

    cout << "Enter the name of the file: \n";
    cin >> filein;
    infile.open (filein,ios::binary);
    if (infile.fail())
       do              
          {       
              cout << "Please enter a file to encrypt: ";     
              cin >> filein;                         
          } while (infile.fail() );

    cout << "Enter the name of the file: \n";
    cin >> filein;
    infile.open (filein,ios::binary);
    if (infile.fail( ))
       {
                   cout<<"Input file opening failed. \n";
                   system("PAUSE");
                   exit(1);
       }

The second works but is not what I am trying to accomplish. I'm sure there is something better than a do while loop for this, but I am not sure which to use. Can I do something like getline(cin,infile)? or can I use some other kind of pointer? Any suggestions or help would be fantstic!

[naaokth]

I'm not very familiar with ifstream, but the
infile.open (filein,ios::binary);
shouldn't be called INTO the loop to avoid infinite loop ?

[mux77]

I am using the ios::binary to open the file in binary mode so I can encrypt it using XOR. If I don't open the text file in binary it doesn't convert back correctly in XOR because of the ASCII traits. Should I move the .open command to the outside? like so:

    cout << "Enter the name of the file: \n";
    cin >> filein;
    if (infile.fail())
    {
       do              
          {       
              cout << "Please enter a file to encrypt: ";     
              cin >> filein;                         
          } while (infile.fail() );
    }
    infile.open (filein,ios::binary);

[mux77]

Nope, that doesn't work. If I move the .open command the the (infile.fail()) has nothing to catch. I don't know why I didn't see that to start. Any other ideas on how to get back to the ciin line?

[naaokth]

This does work for me :

std::ifstream infile;
char* filein;
std::cout << "Enter the name of the file: \n";
std::cin >> filein;
infile.open (filein, std::ios::binary);
while (infile.fail( ))
{
	std::cout << "Input file opening failed. Re-enter the name of the file: \n";
	std::cin >> filein;
	infile.open (filein, std::ios::binary);
}
std::cout << "Input file opening is a success. \n";

[mux77]

I put your code in, maybe I did something wrong but it isn't working for me. this is my entire code. it takes a text file and XORs it for encryption, yes this is my assignment. I have been working on this and had it working until i tried to get this portion to work without having to restart the program. I am new in C++ and this is kicking my butt.

!removed code!

[naaokth]

Well your code does compile without error here.

- I can input a wrong name and it request for another file name until I provide a good one.
- Then it ask for an encryption key
- Next it ask for an output file name without problem even if I give a name of an existing file.
- And finally, I can quit the console without any error, and the output file if effectively encrypted.

[mux77]

I'm using Bloodshed as my compiler, I wonder if that is my problem? Unfortunately that is what I have to use. Thanks for all your help, I might just go back to quiting the program and take the points hit on the grade. This has been driving me nuts!

[naaokth]

I use GCC, and as I do not know Bloodshed I don't know it's particularities.

Do you have any special error report ? or this is still an infinite loop error ?

[mux77]

it is an infinite loop. If I put in the wrong filename it asks for the user to give the correct name over and over. even if I put in the right filename.

[naaokth]

Humm... from what I see (It's 6:20 am here and I'm still working through, so I'm not fully awake ^^) there is no reason to have an infinite loop. (You could add a counter an exit after X fail, but this doesn't fix your problem)

Excuse this (bad) question but do you enter the file name with its dot extension ? ie : "myfile.h" and not "myfile" ? Sometime errors are just an oversight (sorry if the words are not accurate).

[mux77]

yeah, I have been using mydocument.txt. Don't worry, it is 11:40pm here and I have been staring at this most of the day and I'm tired.