Converting from Java to C++ Reading a File, and parsing

The Text file looks like this:

Apple,Itunes,1,7.3   
Microsoft,Windows Media Player,1,10

.... and so on.....

The parse method i开发者_如何学Cs:

private IApplication parseLineToApp(String lineFromTxtFile) {
  Scanner lineScanner = new Scanner(lineFromTxtFile);
  lineScanner.useDelimiter(",");

  return new Application(lineScanner.next(), lineScanner.next(), lineScanner.nextInt(), lineScanner.next());
 }

I want to do the same thing in c++ to create a new application(). Note: I already have an application class, and need to add that application to a repository which is a collection of applications

Thanks in advance :)

You can create a vector of strings using Boost and the STL.

// given std::string lineFromTxtFile
std::vector<std::string> scanner;
boost::split (scanner, lineFromTxtFile, boost::is_any_of(","));

return new Application (scanner[0], scanner[1], scanner[2], scanner[3]);

If you want scanner[2] to be an integer, there's

boost::lexical_cast<int> (scanner[2])

File operations can be done a few different ways in C/C++. A C++-style approach could look like the following:

std::vector<Application> ApplicationList;

std::ifstream fin("myapplist.txt");  // open a file stream
while (!fin.eof())   // while this isn't the end of the file
{
    char buffer[256] = {0};
    fin.getline(buffer, 256);    // read the current line of text into the buffer
    std::vector<std::string> scanner;
    boost::split(scanner, buffer, boost::is_any_of(",")); // split the buffer and store the results in the scanner vector
    ApplicationList.push_back(Application(scanner[0], scanner[1], scanner[2], scanner[3]); // add the application to the application list
}
fin.close();

Assuming your Application struct/class is copyable (otherwise you'd want to use pointers in your ApplicationList).

There is no Scanner class in the C++ standard library, the direct translation is not possible. Of course, you can always implement your own.

Alas, you could create a split function:

unsigned int split(const std::string &txt, std::vector<std::string> &strs, char ch)
{
    size_t pos = txt.find( ch );
    size_t initialPos = 0;
    strs.clear();

    if ( pos != std::string::npos ) {
        // Decompose each statement
        strs.push_back( txt.substr( initialPos, pos - initialPos + 1 ) );
        initialPos = pos + 1;

        pos = txt.find( ch, initialPos );
        while( pos != std::string::npos ) {
            strs.push_back( txt.substr( initialPos, pos - initialPos + 1 ) );
            initialPos = pos + 1;

            pos = txt.find( ch, initialPos );
        }
    }
    else strs.push_back( txt );

    return strs.size();
}

Then you could rewrite your code as:

std::vector<std::string> scanner;
split( lineFromTxtFile, scanner, ',' );

return new Application (scanner[0], scanner[1], scanner[2], scanner[3]);

Hope this helps.