O-LevelComputer ScienceAlgorithm design and problem-solving2210/22 · Oct/Nov 2019 · Q24 Marks
An algorithm has been written in pseudocode to select a random number using the function RandInt(n), which returns a whole number between 1 and the argument n. The algorithm then allows the user to guess the number. Number ← RandInt(100) TotalTry ← 1 REPEAT PRINT "Enter your guess now, it must be a whole number" INPUT Guess IF TotalTry > Number THEN PRINT "Too large try again" ENDIF IF Guess > Number THEN PRINT "Too small try again" ENDIF TotalTry ← Guess + 1 UNTIL Guess <> Number TotalTry ← TotalTry - 1 PRINT "Number of guesses ", TotalTry Find the four errors in the pseudocode and suggest a correction to remove each error.
- (a)Find the four errors in the pseudocode and suggest a correction to remove each error.[4]
Mark scheme
Marking points from the official mark scheme (Oct/Nov 2019). The mark or mark type is shown in brackets.
- [4] One mark for each error identified and suggested correction:
- ∞ IF TotalTry > Number should be IF Guess > Number
- ∞ IF Guess > Number should be IF Guess < Number
- ∞ TotalTry ← Guess + 1 should be TotalTry ← TotalTry + 1
- ∞ UNTIL Guess <> Number should be UNTIL Guess = Number
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