This snippet shows how to use command line arguments as variables in your program. A command line argument is extra information you give a program at runtime, by typing the information after the program name like so:
Linux might look like this:
user$: ./myprogram argument1 argument2
A windows command prompt would look similar to this:
C:\>myprogram arg1 arg2 arg3
It is pretty straightforward,
int argc is the numbers of arguments. 1 is the minimum, which is the text used to invoke the program.
char *argv is a pointer to a character array.
argv is the first element, which is the program name.