SGCA Year 6 — Coding Reference Sheet

🔴🟠🟣 Three Error Types

Type	What happens	Example
Syntax	Won't run	Missing colon
Logic	Wrong answer	= instead of ==
Runtime	Crashes	Divide by zero

Syntax errors — common causes:

# Missing colon if x > 0: # ← needs colon for i in range(5): def greet(name): # = vs == if x == 5: # comparison x = 5 # assignment # Unclosed quote print("hello") # ← both quotes

⚠️ Python tells you the LINE NUMBER in error messages!

🔍 The 5-Step Debug Process

1. READ — Read the error message 2. LOCATE — Find the line with the bug 3. UNDERSTAND — Why is it wrong? 4. FIX — Make ONE change 5. TEST — Run again, verify

Debugging questions to ask:

# What SHOULD happen? # What DOES happen? # Where do they differ? # What changed recently? # Is the logic correct?

💡 Fix ONE thing at a time — then test!

Print debugging:

print("DEBUG: x =", x) print("DEBUG: list =", my_list) print("DEBUG: reached line 15")

🟣 Runtime Errors

Error	Cause
ZeroDivisionError	x / 0
NameError	Undefined variable
IndexError	list[10] (too big)
ValueError	int("abc")
TypeError	"a" + 5
AttributeError	Wrong method

Reading error messages:

Traceback (most recent call last): File "main.py", line 5, in <module> result = 10 / 0 ZeroDivisionError: division by zero # ↑ Error type ↑ Description # Line 5 is where the error is!

🛡️ try / except

Basic structure:

try: result = 10 / 0 except ZeroDivisionError: print("Cannot divide by zero!")

Multiple except blocks:

try: x = int(input("Enter number: ")) result = 100 / x print(result) except ValueError: print("Not a valid number!") except ZeroDivisionError: print("Cannot divide by zero!")

With else and finally:

try: result = 10 / 2 except ZeroDivisionError: print("Error!") else: print("Success:", result) # no error finally: print("Always runs")

⚠️ Only catch errors you expect!

🧪 Writing Tests

Simple test cases:

# Test: is_even() print(is_even(4) == True) # True print(is_even(7) == False) # True print(is_even(0) == True) # True

Using assert:

assert is_even(4) == True assert is_even(7) == False assert get_grade(95) == "A" assert get_grade(85) == "B" print("All tests passed! ✅")

Test types to include:

Type	Example
Normal case	is_even(4) → True
Edge case	is_even(0) → True
Boundary	get_grade(90) → "A"
Negative	is_even(-2) → True

🎯 Edge Cases & Boundaries

Common edge cases:

Situation	Edge case to test
List function	Empty list []
Number function	Zero, negative
String function	Empty string ""
Division	Divisor = 0
Index	First and last item

Boundary testing example:

# Grade: A = 90+, B = 80-89 get_grade(90) # A (at boundary) get_grade(89) # B (just below) get_grade(80) # B (at boundary) get_grade(79) # C (just below) get_grade(0) # F (minimum) get_grade(100) # A (maximum)

💡 Test the EXACT boundary value AND one above/below!

🔧 Logic Error Checklist

Check	Common mistake
Operators	< vs >, == vs !=
Values	Wrong return value
Case	"Nova" ≠ "nova"
Off-by-one	range(1,10) misses 10
Accumulator	Start at 0 vs 1
Condition order	Most specific first

Trace technique:

# Add print statements to trace def get_grade(score): print(f"DEBUG: score={score}") if score >= 90: print("DEBUG: returning A") return "A" # etc...

💡 Trace = follow code step by step manually

🏆 XP Ranks & Worlds

Rank	XP	Icon
Cadet	0	🌱
Explorer	500	🔭
Navigator	1,500	🧭
Captain	3,000	⚡
Admiral	6,000	👑

World	Year	Theme
🌍 Syntax World	3	Sequences
🔮 Algorithm Alley	4	Logic
🌀 Syntax Station	5	Loops
🏜️ Debugging Dunes	6	Debugging
🎨 Creativity Cluster	7	Creative

🔒 Canon Authority: Katarzyna Kalina vel Kalinowska

🏜️ SGCA Year 6 — Coding Reference Sheet