AP CSP Topic 3.6: Conditionals | Big Idea 3 | APCSExamPrep.com

AP CSP Course › Big Idea 3 › Topic 3.6: Conditionals
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3.6
AP CSP — Big Idea 3: Algorithms & Programming
CED Aligned • Exam Ready

Topic 3.6: Conditionals

🎓 High School AP
💻 Python + AP Pseudocode
🎯 30-35% Exam Weight
📚 Interactive Lesson
3.1
Vars
3.2
Data
3.3
Math
3.4
Str
3.5
Bool
3.6
If
3.7
Nest
3.8
Loop
3.9
Algo
3.10
List+
3.11
Srch
3.12
Call
3.13
Proc
3.14
Lib
3.15
Rand
3.16
Sim
3.17
Eff
3.18
Dec

🎯 Learning Objectives

  • Write and trace if/else in Python and AP pseudocode
  • Predict which branch executes for given variable values
  • Identify errors that cause the wrong branch to run
  • Translate between Python and AP pseudocode conditional syntax
📈
Exam Impact: Conditionals are the foundation of algorithm design. They appear in nearly every BI3 MCQ and in Create Task rubric criteria.
💡 Why This Matters

A thermostat is a conditional: IF temperature < 68, turn on heater, ELSE turn off. Every decision-making program runs on this same two-branch structure.

If and If/Else

A conditional executes code only when a condition is true. The else branch runs when the condition is false.

grade = 74
if grade >= 70:
    print("Pass")
else:
    print("Fail")
grade <- 74
IF grade >= 70
{
 DISPLAY("Pass")
}
ELSE
{
 DISPLAY("Fail")
}

Tracing Conditionals

Evaluate the boolean condition with current variable values. Execute only the matching branch -- the other is skipped entirely.

Exam trap: Both branches in an if/else CANNOT both run. If the condition is true, else is skipped. If false, the if block is skipped.

Practice Problems

🔎 Practice MCQ
Given x = 8, what does this code print?
if x > 10:
    print("big")
else:
    print("small")
⚠️ Predict your answer BEFORE clicking.
🔎 Practice MCQ
Which code segments print "yes" when n = 5?
I. if n >= 5: print("yes")
II. if n != 5: print("yes")
III. if n < 10 and n > 0: print("yes")
⚠️ Predict your answer BEFORE clicking.
🔎 Practice MCQ
A student wants to print "discount" when age < 12 OR age >= 65. Their code prints it when age=40. Most likely error?
⚠️ Predict your answer BEFORE clicking.
🎮 Game
Conditional Branch Tracer
Pick what the code prints for the given value. 8 questions.
0
Correct
1/8
Question
0
Streak 🔥
🐛 Trace this code:
0/8
correct
💻 Python Code Editor
Practice Problems
Write Python and check your answer. Paste into Replit for complex programs.
Problem 1 of 3
Print positive if n=7 > 0, else non-positive. Expected: positive
Hint: if n > 0: print('positive') else: print('non-positive')
Problem 2 of 3
Print pass if score=65 >= 60, else fail. Expected: pass
Hint: if score >= 60: print('pass') else: print('fail')
Problem 3 of 3
Spot the bug: should print even for n=4 but always prints odd.
if n % 2 == 1: print('even') else: print('odd')
Hint: Branch labels are swapped. Fix: if n%2==0: print('even') else: print('odd')

Frequently Asked Questions

If the condition is false and there is no else, no code runs -- the program continues to the next statement. This is valid and often intentional.
AP pseudocode uses IF condition { } ELSE { } with curly braces. Python uses indentation with a colon. Both branch on the same condition.
Yes -- that is a nested conditional or elif in Python. Topic 3.7 covers this. Only one path through all branches executes.

🔗 Continue Studying

← BI3 Hub ← 3.5 Boolean Expressions 3.7 Nested Conditionals → Daily Practice Create Task Guide College Board ↗
📦
AP CSP Teacher SuperpackSlides, lesson plans, unit tests for all 5 Big Ideas — $249
Get the Superpack →
← Previous
3.5 Boolean Expressions
Next →
3.7 Nested Conditionals

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