Thread: command line parameters

CppProgrammer33,

Tinker with this:

Code:

#include <iostream>

using namespace std;

int main( int argc, char **argv, char **envp )
{

   auto int i;
   
   for( i = 0; i < argc; i = i + 1 )
   {
      cout << "Argument #" << i << ": " << argv[i] << endl;
   }

// nullptr is undeclared in g++ (GCC) 3.4.4
//   for( i = 0; nullptr != envp[i]; i = i + 1 )
   for( i = 0; NULL != envp[i]; i = i + 1 )
   {
      cout << "Environment variable #" << i << ": " << envp[i] << endl;
   }
   
   return 0;
}

I tried using nullptr, but it looks like it's time to upgrade the software. I think that's the full signature for main, in addition to the parameters passed to the program by the OS from the user when it is invoked, there are a collection of environment variables which may also be accessed by the program.

Best Regards,

New Ink -- Henry

Originally Posted by laserlight

Perhaps you should test with this:

Code:

#include <iostream>
#include <cstring>

int main(int argc, char* argv[])
{
    using namespace std;

    if (argc > 1)
    {
        if (strcmp(argv[1], "-Dev") == 0)
        {
            cout << "Valid command line argument!";
        }
        else
        {
            cout << "Invalid command line argument: '" << argv[1] << "'";
        }
    }
    else
    {
        cout << "No command line argument.";
    }

    cout << endl;
}

Note that you have to enter -Dev as the command line argument, not say, -dev or -Devmode.exe.

This is correct.

@threadstarter

I'm not sure how you run the file, because the following will work just fine:

1) Run
2) cmd.exe
3) Browse to the folder your program exe is in (cd c:/projects/../)
4) type in: YourApplicationName.exe -Dev

Simple