Flashcards · 9618 · AS Topic 11

Programming (AS Level) flashcards

15 cards on AS Topic 11, subtopics 11.1 to 11.3. Pick a subtopic or study them all.

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What is the assignment operator in 9618 pseudocode?: ← , for example Count ← Count + 1. The = sign is used for comparison and in CONSTANT declarations, not for assignment.
How do you take input and give output in 9618 pseudocode?: INPUT Name OUTPUT "Hello ", Name OUTPUT can print several items separated by commas.
Which string functions does the 9618 pseudocode guide give?: Examples: LENGTH(s) gives the number of characters; LEFT(s, x) and RIGHT(s, x) give x characters from either end; MID(s, x, y) gives y characters starting at position x. & joins (concatenates) strings.
What do INT and RAND do in 9618 pseudocode?: INT(x) returns the integer part of x (e.g. INT(27.9) is 27). RAND(x) returns a random real number from 0 up to but not including x.
What are integer division and modulo? Give 17 and 5 as an example.: Integer division gives the whole-number quotient: 17 divided by 5 gives 3. Modulo gives the remainder: 17 modulo 5 gives 2.

What is the structure of an IF statement in 9618 pseudocode?: IF condition THEN statements ELSE statements ENDIF
What is the structure of a CASE statement in 9618 pseudocode?: CASE OF identifier value1 : statement value2 : statement OTHERWISE statement ENDCASE
What is the structure of a count-controlled loop in 9618 pseudocode?: FOR Count ← 1 TO 10 statements NEXT Count STEP can set the increment, e.g. FOR i ← 10 TO 0 STEP -2.
What is the difference between a pre-condition and a post-condition loop?: Pre-condition (WHILE condition … ENDWHILE): the condition is tested first, so the body may run zero times. Post-condition (REPEAT … UNTIL condition): the body always runs at least once.
When does a WHILE loop stop and when does a REPEAT loop stop?: WHILE repeats while its condition is TRUE and stops when it becomes FALSE. REPEAT … UNTIL repeats until its condition becomes TRUE.

What is the difference between a procedure and a function?: A function returns a single value and is used in an expression. A procedure performs a task and is run with CALL; it returns no value directly.
How do you write a function in 9618 pseudocode?: FUNCTION Square(Num : INTEGER) RETURNS INTEGER RETURN Num * Num ENDFUNCTION
How do you write and call a procedure in 9618 pseudocode?: PROCEDURE Greet(Name : STRING) OUTPUT "Hello ", Name ENDPROCEDURE CALL Greet("Ali")
What is the difference between passing a parameter BYVAL and BYREF?: BYVAL: a copy of the value is passed, so the original variable is not changed. BYREF: the address is passed, so changes made in the subroutine change the original. If neither is stated, BYVAL is assumed.
What is the difference between a parameter and an argument?: A parameter is the variable named in the subroutine header. An argument is the actual value passed to it when the subroutine is called.