When you start a command-line program, everything you type after the name is passed as an argument to the program. Arguments can be separated with whitespace characters. To pass command line argument in XCODE, select the project from the title bar and select Edit Schema, then select the Run Debug and pass in the argument as shown in the below image.
Other way is following commands from the Main Menu:
- Go to Product
- Scheme – Edit Scheme
- Find Run in the left hand column
- Click the Arguments tab