passing ios::flag as a parameter ..

I have function saveData() which writes to a text file. I would like to tell it whether to append ios::app or create new ios::out ... How do i pass these flags as a parameter to saveData(...)?

One option is to have a std::ostream as the parameter. If you really want to open the file according to a filename and format flags then std::ios::fmtflags should be the type of the format flags parameter.

Quote:

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Originally Posted by laserlight

One option is to have a std::ostream as the parameter. If you really want to open the file according to a filename and format flags then std::ios::fmtflags should be the type of the format flags parameter.

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should it be this?

Code:

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void saveData(std::ios::fmtflags flag)
{
              ofstream outfile;
        char filename[MAX_PATH] = "contract.txt";
        outfile.open(filename, flag);
}

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Quote:

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Originally Posted by csonx_p

should it be this?

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It is probably correct but if you really need the filename variable, it would be better to write it as:

Code:

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char filename[MAX_PATH] = "contract.txt";
ofstream outfile(filename, flag);

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Actually, if you need filename, why not make it a std::string?

Quote:

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Originally Posted by laserlight

Actually, if you need filename, why not make it a std::string?

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because

Code:

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void open ( const char * filename, ios_base::openmode mode = ios_base::out );

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Use the c_str() member function, e.g.,

Code:

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std::string filename = "contract.txt";
ofstream outfile(filename.c_str(), flag);

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EDIT:
By the way, it looks like I got it wrong: the std::ios::fmtflags is for format flags (duh). On the other hand, the source you quoted gives std::ios_base::openmode, so perhaps you can try std::ios::openmode as the type.

Quote:

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Originally Posted by csonx_p

because

Code:

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void open ( const char * filename, ios_base::openmode mode = ios_base::out );

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You can call c_str() on the string to get a char *...