Practice Nested Conditionals in CS Thinking

Use these practice problems to test your method after reviewing the concept explanation and worked examples.

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Quick Recap

Conditional statements placed inside other conditional statements, creating multiple levels of decision-making. The inner condition is only evaluated when the outer condition is true, allowing programs to model complex, multi-step decisions.

Nested conditionals are like a decision tree — first you ask one question, and depending on the answer, you ask a follow-up question.

Showing a random 20 of 50 problems.

Example 1

hard
The following deeply nested code is hard to read. Refactor it to be clearer: IF a > 0 THEN: IF b > 0 THEN: IF c > 0 THEN: OUTPUT 'All positive'. ELSE: OUTPUT 'c not positive'. ELSE: OUTPUT 'b not positive'. ELSE: OUTPUT 'a not positive'.

Example 2

medium
Write nested conditionals for a cinema discount: Seniors (age >= 65) get 50% off. Children (age < 12) get 30% off. Everyone else pays full price, but students with a valid ID get 20% off. Trace for age=20, isStudent=TRUE.

Example 3

medium
Trace: u_logged_in=True, u_admin=False. `if u_logged_in: if u_admin: print('panel') else: print('home') else: print('login')`. Output?

Example 4

medium
How many distinct outputs can `if a: if b: P() else: Q() else: R()` produce, and what are they?

Example 5

easy
In `if A: if B: X`, X runs only when which boolean expression is true?

Example 6

medium
Trace: x=-2. `if x>=0: if x==0: print('zero') else: print('pos') else: if x>=-5: print('small neg') else: print('big neg')`. Output?

Example 7

medium
Trace: x=4, y=4. `if x==y: if x>0: print('equal pos') else: print('equal nonpos') else: print('diff')`. Output?

Example 8

challenge
Trace: n=6. `if n>0: if n%2==0: if n>4: print('A') else: print('B') else: print('C') else: print('D')`. Output, and how deep is the taken path?

Example 9

medium
Trace: a = 7, b = 2. `if a > 5: if b > 5: print('both') else: print('a only') else: print('neither')`. Output?

Example 10

medium
Given `if A: if B: X else: Y else: Z`, with A=True, B=False, which runs and is Z evaluated?

Example 11

medium
Refactor `if a: if b: if c: do()` using guard clauses for early exit.

Example 12

easy
Trace: x = -3. `if x >= 0: print('non-neg') else: if x < -5: print('very neg') else: print('neg')`. Output?

Example 13

medium
Trace: t=5 (hour). `if t<12: if t<6: print('night') else: print('morning') else: print('afternoon')`. Output?

Example 14

medium
Trace: n=15. `if n%3==0: if n%5==0: print('FizzBuzz') else: print('Fizz') else: if n%5==0: print('Buzz') else: print(n)`. Output?

Example 15

easy
Trace: n=4. `if n%2==0: if n>10: print('big even') else: print('small even')`. Output?

Example 16

hard
Trace: a=3, b=7, c=2. `if a<b: if b<c: print('asc') else: if a<c: print('mid') else: print('a<b,c<a')`. Output?

Example 17

easy
Trace the following code when age = 15 and hasTicket = TRUE: IF age >= 12 THEN: IF hasTicket THEN: OUTPUT 'Enter'. ELSE: OUTPUT 'Buy a ticket'. ELSE: OUTPUT 'Too young'.

Example 18

easy
Trace: x=10. `if x>0: if x>5: print('big') else: print('small')`. Output?

Example 19

medium
Trace: a=2,b=8,c=5. `if a<b: if b<c: print('asc') else: if a<c: print('a<c<b') else: print('other')`. Output?

Example 20

easy
Rewrite `if rain: if cold: stay_in()` as one if-statement using AND.
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Related Concepts

Selection