A procedure Square() will take an integer value in the range 1 to 9 as a parameter and output a number square. The boundary of a number square is made up of the character representing the parameter value. The inside of the number square is made up of the asterisk character (*). Parameter value 1 2 3 4 ... 9 Output 1 22 22 333 3*3 333 4444 4**4 4**4 4444 ... 999999999 9*******9 9*******9 9*******9 9*******9 9*******9 9*******9 9*******9 999999999 The pseudocode OUTPUT command starts each output on a new line. For example, the following three OUTPUT statements would result in the outputs as shown: OUTPUT "Hello" OUTPUT "ginger" OUTPUT "cat" Resulting output: Hello ginger cat

Mark scheme

Marking points from the official mark scheme (May/June 2023). The mark or mark type is shown in brackets.

1. [6] Example of iterative solution: PROCEDURE Square(Dim : INTEGER) DECLARE Count : INTEGER DECLARE ThisChar : CHAR DECLARE StringA, StringB : STRING CONSTANT FILLER = '*' StringA ← "" ThisChar ← NUM_TO_STR(Dim) FOR Count ← 1 TO Dim StringA ← StringA & ThisChar //build up first & last line NEXT Count StringB ← ThisChar FOR Count ← 1 TO Dim – 2 StringB ← StringB & FILLER //build up intermediate line NEXT Count StringB ← StringB & ThisChar // add final digit OUTPUT StringA FOR Count ← 1 TO Dim – 2 OUTPUT StringB NEXT Count IF Dim <> 1 THEN OUTPUT StringA ENDIF ENDPROCEDURE For loop-based solutions, mark as follows: 1 Procedure heading and ending including parameter 2 Loop using parameter, containing attempt to construct first line / last line 3 Construct first line / last line 4 Attempt at loop to construct intermediate line 5 Output first / last line of square when Dim > 2 6 Output all intermediate lines in a loop 7 Correct output of first two squares Note: Max 6 marks
2. [6] Example of selection-based solution: PROCEDURE Square(Dim : INTEGER) DECLARE Count : INTEGER CASE OF Dim 1 : OUTPUT "1" 2 : OUTPUT "22" OUTPUT "22" 3 : OUTPUT "333" OUTPUT "3*3" OUTPUT "333" 4 : OUTPUT "4444" FOR Count ← 1 TO 2 OUTPUT "4**4" NEXT Count OUTPUT "4444" 5 : OUTPUT "55555" FOR Count ← 1 TO 3 OUTPUT "5***5" NEXT Count OUTPUT "55555" 6 : OUTPUT "666666" FOR Count ← 1 TO 4 OUTPUT "6****6" NEXT Count OUTPUT "666666" 7 : OUTPUT "7777777" FOR Count ← 1 TO 5 OUTPUT "7*****7" NEXT Count OUTPUT "7777777" 8 : OUTPUT "88888888" FOR Count ← 1 TO 6 OUTPUT "8******8" NEXT Count OUTPUT "88888888" 9 : OUTPUT "999999999" FOR Count ← 1 TO 7 OUTPUT "9*******9" NEXT Count OUTPUT "999999999" ENDCASE ENDPROCEDURE For in-line / selection-based solutions, mark as follows: 1 Procedure heading and ending including parameter 2 Correct use of parameter to select all required squares 3 Correct output of first two squares 4 At least six squares correctly output 5 At least one loop to output lines with multiple asterisks 6 All number squares output correctly