Parse Command line arguments within a function

Question

This is my requirement -

I have to get the inputs from Command line in the form

-des <destIP> -prot <tcp/udp> -min <minutes>

There are several programs that suggest how to parse these values through the argc and argv parameters of main() function. But I want a function which gets the iput line and then parse it.

The function would be -

void GetArguments()
{
    cout << "Enter arguments ..." << endl;
    cin >> inputStr;//eg: inputStr = "-des 127.0.0.1 -prot tcp -min 60"

    //code to parse the input arguments and get values of dest IP, protocol and time
}

How do I get the values I need?

You'll need to pass the arguments of the main() function to this function (GetArguments()). There's no other way to get the input line. — πάντα ῥεῖ
– πάντα ῥεῖ, Commented Aug 19, 2014 at 6:49

Remy Lebeau · Accepted Answer · 2014-08-19 16:05:44Z

2

Use CommandLineToArgvW() to parse a wchar_t*, such as from a std::wstring, into a wchar_t*[] array that you can loop through, just like with argv/argc. For example:

void GetArguments()
{
    std::wstring inputStr;
    std::wcout << L"Enter arguments ..." << std::endl;
    std::wcin >> inputStr;

    int numArgs;
    LPWSTR *args = CommandLineToArgvW(inputStr.c_str(), &numArgs);
    if (args)
    {
        for (int i = 0; i < numArgs; ++i)
        {
            // use args[i] as needed...
        }
        LocalFree(args);
    }
}

This is a Windows-specific solution, since your question is tagged for Visual Studio. If you are looking for a pure C++ solution, you will have to tokenize inputStr manually, splitting it on whitespace and quotations as needed. There are tons of examples of that floating around.

edited Aug 19, 2014 at 16:05

answered Aug 19, 2014 at 7:00

Remy Lebeau

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2 Comments

user3164272 Over a year ago

What is the header that I need to include for LPWSTR and CommandLineToArgvW()?

Remy Lebeau Over a year ago

If you read the documentation I linked you to, it tells you that CommandLineToArgvW() is declared in Shellapi.h. As for LPWSTR, it is declared in WinNT.h, which is included by Windows.h.

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