How Programs Work: Functions & Memory Explained

What's a Function?

Think of functions like Lego blocks:

• Each block has a special job (add numbers, check passwords)
• Blocks snap together to make bigger programs
• You can examine one block without breaking others

🔄 Function Life Cycle

1. Start: "Hey computer, run this block!"
2. Work: Does its special job
3. Finish: "I'm done, here's your result!"

📚 The Memory Stack

Like stacking lunch boxes:

        ┌────────────┐
        │ Current    │ ← Top
        │ Function   │
        ├────────────┤
        │ Previous   │
        │ Function   │
        └────────────┘
        

Last Added → First Removed (LIFO)

🔍 Reverse Engineering Tips

• Look for patterns in code blocks
• Track how data moves between functions
• Watch memory stack changes

Real World Example

Simple copy program:

Start Program │ ▼ Open File → Read → Write → Close

Each arrow represents a function call!

❓ Frequently Asked Questions

Why use functions?

They help organize code like puzzle pieces - easier to fix and reuse!

What's a stack overflow?

When too many lunch boxes stack up and fall over! (Too many function calls)

How do hackers use this?

By studying how blocks connect, they can find secret passages in programs!

💡 Pro Tips

• Name functions clearly (like "CalculateScore")
• Keep stacks tidy - clean up after functions
• Use tools like Ghidra to see function maps