Some command line programs take in arguments when you run them. For example: ping yahoo.com . The ping program takes in a URL as an argument, then the program will launch and attempt to send packets of information to the URL and see if there's a response.

We can also write comamnd line programs with arguments. To do this, we need to add a couple of arguments to main:

int main( int argCount, char* args[] )
{
}

In this case, any text given after the program name will be stored in args[1] and after (the program name is in args[0].) char* args[] is an array of c-style strings, though we can convert them into other data types. The int argCount tells us how many arguments were passed into the program. If the user doesn't pass in enough arguments, we could display an error message and what we expect the arguments to be.

For the time being, don't worry about "int", "char*", or "[ ]", but we will learn about these later. The arguments item is essentially a list of input items passed to the program. argCount will also contain the amount of arguments passed in. So, if a program is run like this:

./program ONE two THREE

Then it would have 4 total arguments (the program name counts as one), with "ONE" being argument #1, "two" being argument #2, and "THREE" being argument #3.

We can convert the arguments to different data types. The following code snippet shows examples:

int main( int argCount, char* args[] )
{
    if ( argCount < 5 )
    {
        cerr << "Not enough arguments!" << endl;
        return 1;
    }

    int myInteger = stoi( args[1] );
    float myFloat = stof( args[2] );
    string myString = string( args[3] );
    char myChar = args[4][0];
}

Generally in the starter code I'll handle checking for enough arguments and set up the input variables and cast the arguments to them, so you won't have to worry about this part of a program's setup.

WAVE accessibility score: 9.8/10