A REPEAT…UNTIL loop with two ways to stop

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Quick Questions

Shade in the A or B circle for each question.

1. A loop ends with UNTIL Guess = Secret OR Tries = 5. The guess is wrong but Tries is 5. Does the loop stop?

A Yes, Tries = 5 is TRUE, so the whole OR condition is TRUE

B No, the guess is still wrong, so it keeps going

2. Which UNTIL line gives the guessing game two ways to stop?

A UNTIL Guess = Secret OR Tries = 5

B UNTIL Guess = Secret AND Tries = 5

3. In UNTIL Guess = Secret OR Tries = 5, Guess = Secret is TRUE and Tries is only 2. What happens?

A The loop keeps repeating until Tries reaches 5

B The loop stops, because one TRUE part is enough

4. When does a REPEAT...UNTIL loop go around again?

A While the UNTIL condition is TRUE

B While the UNTIL condition is FALSE

5. The guess is wrong and Tries = 3. What is UNTIL Guess = Secret OR Tries = 5?

A FALSE, so the loop repeats

B TRUE, so the loop stops

Match the Pairs

Draw a line connecting each item on the left to its match on the right.

Left column		Right column
1UNTIL Guess = Secret OR Tries = 5		AREPEAT INPUT Mark UNTIL Mark >= 0 AND Mark <= 100
2UNTIL Mark >= 0 AND Mark <= 100		BStop repeating as soon as the guess is correct or the player has used 5 tries, whichever happens first.
3A guessing game that must stop when the guess is right or the tries have run out		CAND is used instead of OR. The loop only stops if the guess is correct and the fifth try is used at the same time, so a correct guess on try 2 does not end it.
4Keep asking for a mark until it is inside the valid range of 0 to 100		DStop repeating only when the mark is both at least 0 and at most 100, so the input is valid.
5UNTIL Guess = Secret AND Tries = 5		EREPEAT INPUT Guess Tries ← Tries + 1 UNTIL Guess = Secret OR Tries = 5
6UNTIL Mark >= 0 OR Mark <= 100		FOR is used instead of AND. Every number is at least 0 or at most 100, so the condition is always TRUE and invalid marks like 150 or -5 are accepted.

Definitions

UNTIL Guess = Secret OR Tries = 5

Fill in the Blanks

Complete each line of code by filling in the missing parts.

REPEAT INPUT Guess UNTIL Guess = Secret __ Tries = 5

REPEAT INPUT Guess _____ Guess = Secret OR Tries = 5

REPEAT Tries ← Tries + 1 UNTIL Guess = Secret OR _____ = 5

REPEAT INPUT Mark UNTIL Mark >= 0 ___ Mark <= 100

REPEAT INPUT Mark UNTIL Mark __ 0 AND Mark <= 100

Spot the Error

Shade in the letter of the line that contains an error.

Question 1

A Tries ← 5

B REPEAT

C INPUT Guess

D Tries ← Tries + 1

E UNTIL Guess=Secret OR Tries=5

Question 2

A Tries ← 0

B REPEAT

C Tries ← Tries

D INPUT Guess

E UNTIL Guess=Secret OR Tries=5

Question 3

A REPEAT

B INPUT Mark

C UNTIL Mark>=0 OR Mark<=100

Question 4

A REPEAT

B OUTPUT Mark

C UNTIL Mark>=0 AND Mark<=10

Question 5

A OUTPUT "Enter a mark"

B REPEAT

C INPUT Mark

D UNTIL Mark>=0 AND Mark>=100

Answer Key

A REPEAT…UNTIL loop with two ways to stop

Section A: Quick Questions

A — Yes, Tries = 5 is TRUE, so the whole OR condition is TRUE

A — UNTIL Guess = Secret OR Tries = 5

B — The loop stops, because one TRUE part is enough

B — While the UNTIL condition is FALSE

A — FALSE, so the loop repeats

Section B: Match the Pairs

UNTIL Guess = Secret OR Tries = 5 → Stop repeating as soon as the guess is correct or the player has used 5 tries, whichever happens first.

UNTIL Mark >= 0 AND Mark <= 100 → Stop repeating only when the mark is both at least 0 and at most 100, so the input is valid.

A guessing game that must stop when the guess is right or the tries have run out → REPEAT INPUT Guess Tries ← Tries + 1 UNTIL Guess = Secret OR Tries = 5

Keep asking for a mark until it is inside the valid range of 0 to 100 → REPEAT INPUT Mark UNTIL Mark >= 0 AND Mark <= 100

UNTIL Guess = Secret AND Tries = 5 → AND is used instead of OR. The loop only stops if the guess is correct and the fifth try is used at the same time, so a correct guess on try 2 does not end it.

UNTIL Mark >= 0 OR Mark <= 100 → OR is used instead of AND. Every number is at least 0 or at most 100, so the condition is always TRUE and invalid marks like 150 or -5 are accepted.

Section C: Definitions

UNTIL Guess = Secret OR Tries = 5 — A REPEAT loop whose UNTIL condition uses OR stops as soon as either part becomes TRUE, so the loop has two ways to end: a correct guess or running out of tries.

Section D: Fill in the Blanks

REPEAT
  INPUT Guess
UNTIL Guess = Secret OR Tries = 5

REPEAT
  INPUT Guess
UNTIL Guess = Secret OR Tries = 5

REPEAT
  Tries ← Tries + 1
UNTIL Guess = Secret OR Tries = 5

REPEAT
  INPUT Mark
UNTIL Mark >= 0 AND Mark <= 100

REPEAT
  INPUT Mark
UNTIL Mark >= 0 AND Mark <= 100

Section E: Spot the Error

A — Tries must start at 0. Starting at 5 means it becomes 6 after the first guess and never equals 5, so only a correct guess can end the loop. It should be Tries ← 0.

C — Tries never increases, so Tries = 5 can never become TRUE. The second way to stop is lost. It should be Tries ← Tries + 1.

C — Every number is at least 0 or at most 100, so OR is always TRUE and invalid marks are accepted. Validation needs AND so both parts are TRUE before the loop stops.

B — The loop never reads a new value, so Mark never changes and the UNTIL condition is never met. The line should be INPUT Mark.

D — Mark>=100 is the wrong test for the upper limit, so only marks of 100 or more would be accepted. The second part should be Mark<=100.