How to open a filename that the user entered?

Question

    required.close();
    destined.close();
}

This program should ask the user to enter a filename and an output filename. The input filename should have a message that would be encrypted or decrypted, depends on the user's choice. The program should have 3 functions, one to check the file's existence, one to encrypt/decrypt each character and one to encrypt/decrypt the whole file.

Answer 1

There are some errors and some things to change:

• in the encChar function this is wrong: if (flag = true). You should use a comparison operator (==):

  `if (flag == true)`
  

  Someone prefers this form (comparison terms swapped):

  `if (true == flag)`
  

  because wrong assignments are detected.

• in the encFile function it should be:

  ofstream destined(outFile.c_str());
  

  It's a good idea to enable warnings (e.g. with GCC/CLANG use -Wansi -Wall -Wextra) so that unused variables/parameters are detected (in your case the string outFile input parameter).

Pay attention at Simple's advice (Try using an absolute path. It's probably related to your program having a different working directory to what you expect) and your program should work.

You could improve your code with some other changes:

• place variables in the narrowest scope possible and initialize variables in the declaration, e.g.

  ifstream required;
  required.open(inFile.c_str());
  

  should be

  ifstream required(inFile.c_str());
  

  (and check for error before using the stream).

• using namespace std is considered a bad practice.

• coding style and formatting are pretty arbitrary, but code is much easier to follow if you always use the same style.

• don't use global variables