Cambridge International AS& A Level DC (JC/CT) 188579/4 © UCLES 2020[Turn over This document has16pages. Blank pages are indicated. * 5 4 7 9 1 0 0 9 4 4 * COMPUTER SCIENCE9608/23 Paper 2 Fundamental Problem-solving and Programming SkillsOctober/November2020 2 hours You must answer on the question paper. No additional materials are needed. INSTRUCTIONS ●Answerallquestions. ●Use a black or dark blue pen. ●Write your name, centre number and candidate number in the boxes at the top of the page. ●Write your answer to each question in the space provided. ●Donotuse an erasable pen or correction fluid. ●Donotwrite on any bar codes. ●You may use an HB pencil for any diagrams, graphs or rough working. ●Calculators mustnotbe used in this paper. INFORMATION ●The total mark for this paper is 75. ●The number of marks for each question or part question is shown in brackets [ ]. ●No marks will be awarded for using brand names of software packages or hardware.
2 9608/23/O/N/20© UCLES 20201(a)A programmer uses the process of stepwise refinement to break down a problem. Explain the purpose of stepwise refinement. ................................................................................................................................................... ................................................................................................................................................... ................................................................................................................................................... .............................................................................................................................................[2] (b)Programming languages support different data types. These usually includeSTRINGand REAL. Complete the table by givingfour otherdata typesandan example data value for each. Data typeExample data value [4] (c)An experienced programmer is working on a program that is written in a language she is not familiar with. (i)Stateonefeature of the program that she should be able to recognise. ........................................................................................................................................... .....................................................................................................................................[1] (ii)State the type of skill that would allow her to recognise this feature. ........................................................................................................................................... .....................................................................................................................................[1] (d)Givethreemethods that may be used to identify and locate errors in a programafter it has been written. You may includeonefeature found in a typical Integrated Development Environment (IDE). 1................................................................................................................................................ 2................................................................................................................................................ 3................................................................................................................................................ [3]
3 9608/23/O/N/20© UCLES 2020[Turn over 2(a)An algorithm is needed to input a list of numbers representing test marks for a class of 30 students. The algorithm will output the number of students who have a mark greater than 75. It will also output the average mark for the class. Document the algorithm usingstructured English. ................................................................................................................................................... ................................................................................................................................................... ................................................................................................................................................... ................................................................................................................................................... ................................................................................................................................................... ................................................................................................................................................... ................................................................................................................................................... ................................................................................................................................................... ................................................................................................................................................... ................................................................................................................................................... ................................................................................................................................................... .............................................................................................................................................[8]
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