Interactive Computer Science Tutoring

Learn programming concepts interactively

C Command Line Arguments
Learn argc and argv through the Mail Sorting Office metaphor
Learning Progression - Mail Room Training

Mail Counter Introduction

Understanding argc as a simple counter

"How many mail pieces did we receive today?"

Return Address Examination

Accessing argv[0] (program name)

"What's the return address on this mail?"

Reading Delivery Addresses

Accessing argv[1], argv[2], etc.

"Where are we delivering these messages?"

Mail Room Validation

Checking if enough arguments were provided

"Do we have enough information to deliver this mail?"

Advanced Mail Processing

Parsing different argument types and patterns

"Different types of mail need different handling"

Mail Room Control Panel
Add and manage command line arguments (mail pieces)
argv[0]./myprogramReturn Address
Mail Room Quality Control
Activate validation rules to check mail processing requirements

No validation rules active

Missing required arguments

Too many arguments provided

Second argument must be a number

Current Learning Focus

Mail Counter Introduction

Concept: argc counts the total number of arguments

Mail Room Metaphor: "How many mail pieces did we receive today?"

Interactive Demonstration

1

argc (argument count) = 1

This includes the program name (return address) + delivery addresses

Command Line Arguments - Key Concepts

argc (Argument Count)

Integer that contains the number of command line arguments, including the program name. Always ≥ 1.

argv[0] (Program Name)

Always contains the name of the program as it was called. This is like the "return address" on a mail piece.

argv[1], argv[2]...

The actual command line arguments provided by the user. Each is a null-terminated string.

Validation

Always check argc before accessing argv elements to avoid segmentation faults.

Common Pitfalls

Off-by-one errors, assuming arguments exist, forgetting argv[0] is the program name.

Best Practices

Provide usage messages, validate input, handle edge cases gracefully.