O-LevelComputer ScienceAlgorithm design and problem-solving2210/22 · May/June 2025 · Q47 Marks
State one reason for using a verification check when inputting data.
- (a)State one reason for using a verification check when inputting data.[1]
- (b)Write the pseudocode for an algorithm to perform a double entry verification check, using the following criteria: • Input 10 numbers and store them in the array Numbers[] • Input the same 10 numbers again; as each number is input, compare it with its corresponding number in the array Numbers[] Ο if the numbers match, move on to the next number Ο if the numbers do not match, display both numbers and ask for the number to be re-entered Ο store the re-entered number in the corresponding array location and move on to the next number. • When all the numbers have been checked, display a message to say the check has been completed. You do not need to declare any arrays or variables for this algorithm.[6]
Mark scheme
Marking points from the official mark scheme (May/June 2025). The mark or mark type is shown in brackets.
- [1] (a) To check that the value entered has not changed on input.
- [6] (b) One mark per mark point, max six MP1 At least one appropriate working loop MP2 First inputs of numbers all stored in array Numbers MP3 Correct second input made for each number MP4 Working selection statement to compare first and second inputs one at a time MP5 If numbers don't match, appropriate output, including both values input and a message requiring re-input MP6 New input stored in current array location (replacing original input) MP7 Final output confirming completion, outside loop.
- (b) For example, // variable and array declarations or initialisations // are not required for this question FOR Index ← 1 TO 10 INPUT Numbers [Index] NEXT Index FOR Index ← 1 ΤΟ 10 INPUT CheckNumber IF CheckNumber <> Numbers [Index] THEN OUTPUT CheckNumber, " and ", Numbers[Index], " do not match. Please re-enter the number. " INPUT Numbers [Index] ENDIF NEXT Index OUTPUT "The check has been completed."
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