Writing 0478 Pseudocode From Memory

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Exam Context and Importance

Paper 2 (1h45m, 75 marks) requires pseudocode answers; programming-language code earns no marks.
The only exception is the final 15-mark scenario question, where pseudocode, Python, VB, or Java are accepted.
No pseudocode reference sheet is provided in the exam; you must reproduce constructs from memory.
Mark schemes are written in Cambridge pseudocode, so accuracy in syntax is vital to earn marks.
Focus on logic over syntax, but incorrect pseudocode loses marks even if logic is right.

General Style Rules

Keywords are in UPPER CASE (e.g., IF, THEN, ELSE, ENDIF, REPEAT, UNTIL, WHILE, DO, ENDWHILE, FOR, NEXT, CASE OF, OTHERWISE, ENDCASE, DECLARE, CONSTANT, INPUT, OUTPUT, PROCEDURE, ENDPROCEDURE, CALL, FUNCTION, RETURNS, RETURN, ENDFUNCTION, OPENFILE, READFILE, WRITEFILE, CLOSEFILE, ARRAY, OF, STEP).
Identifiers use Pascal case (e.g., NumberOfPlayers, TotalToPay); start with a capital letter, contain only letters/digits, no underscores or accented letters.
Identifiers are case-insensitive (Countdown = CountDown) and must not be keywords.
Single letters allowed only conventionally: i, j for indices, X, Y for coordinates.
Indentation: 4 spaces for block contents, 2 spaces for THEN/ELSE and CASE clauses.
Comments start with // and run to end of line; multi-line comments use // on each line.

Data Types, Declarations, and Constants

Five basic data types: INTEGER, REAL, CHAR, STRING, BOOLEAN.
Literals: integers (5, -3), reals always with digit both sides of point (4.7, 0.3, -4.0, 0.0), chars in single quotes ('x'), strings in double quotes ("text"), Booleans TRUE/FALSE.
Declaration syntax: `DECLARE <identifier> : <data type>` (e.g., `DECLARE Counter : INTEGER`).
Constant syntax: `CONSTANT <identifier> ← <value>` (e.g., `CONSTANT HourlyRate ← 6.50`).
Constant value must be a literal only; never a variable, constant, or expression.

Assignment and Operators

Assignment uses left arrow `←` (e.g., `Counter ← 0`); `=` is only for equality in conditions.
Arithmetic operators: `+`, `-`, `×`, `/`, `^` (power). Multiplication/division bind tighter than addition/subtraction; use parentheses for clarity.
Integer division: `DIV(x, y)` returns quotient with fraction discarded (e.g., `DIV(10,3)` = 3); `MOD(x, y)` returns remainder (e.g., `MOD(10,3)` = 1).
Relational operators: `=`, `<`, `≤`, `>`, `≥`, `<>` (not equal).
Logical operators: AND, OR, NOT; operands and results are BOOLEAN.

Input and Output

`INPUT <variable>` reads a single value into a variable (may be an array element).
`OUTPUT <value1>, <value2>, ...` outputs comma-separated values.
`INPUT` does not display a prompt; use a separate `OUTPUT` before it.
Example: `OUTPUT "You have ", Lives, " lives left"`.

Selection (IF and CASE)

IF syntax: `IF <condition> THEN <statements> ENDIF` (with optional ELSE).
THEN and ELSE clauses are indented 2 spaces; nested IFs continue this pattern.
CASE syntax: `CASE OF <identifier> <value> : <statement> ... OTHERWISE <statement> ENDCASE`.
Case clauses are tested in order; first match runs, then control jumps to after ENDCASE.
OTHERWISE must be last; each case should be a single value; complex logic better as IF.
Example: `CASE OF Move 'W' : Position ← Position - 10 'E' : Position ← Position + 10 OTHERWISE OUTPUT "Beep" ENDCASE`.

Iteration (Loops)

FOR loop: `FOR <identifier> ← <value1> TO <value2> <statements> NEXT <identifier>`; counter must be INTEGER.
FOR loop runs inclusive of end values; if start > end, body runs zero times; STEP can be added (e.g., `FOR Index ← 10 TO 1 STEP -1`).
REPEAT...UNTIL: `REPEAT <statements> UNTIL <condition>` — body always runs at least once, condition tested at bottom.
WHILE...DO...ENDWHILE: `WHILE <condition> DO <statements> ENDWHILE` — condition tested at top, body may run zero times.
Do not confuse REPEAT (post-condition) with WHILE (pre-condition).

Arrays

Declaration: `DECLARE <name> : ARRAY[<lower>:<upper>] OF <type>` (e.g., `DECLARE StudentNames : ARRAY[1:30] OF STRING`).
2D arrays: `DECLARE NoughtsAndCrosses : ARRAY[1:3, 1:3] OF CHAR`.
State lower bound explicitly (usually 1) because default varies.
Access elements with brackets: `StudentNames[1] ← "Ali"`, `NoughtsAndCrosses[2,3] ← 'X'`.
Fill arrays using loops: `FOR Index ← 1 TO 30 StudentNames[Index] ← "" NEXT Index`.

String and Library Routines

`LENGTH("Happy Days")` returns 10.
`SUBSTRING("Happy Days", 1, 5)` returns "Happy" (identifier, start, length).
`UCASE("Happy")` returns "HAPPY"; `LCASE('W')` returns 'w'.
`ROUND(<identifier>, <places>)` rounds a REAL to given decimal places.
`RANDOM()` returns a random number between 0 and 1 inclusive.
Example: `Value ← ROUND(RANDOM()×6, 0)` gives a whole number 0-6.

Procedures and Functions

Procedure definition: `PROCEDURE <name>(<params>) <statements> ENDPROCEDURE`; called with `CALL <name>(<args>)`.
Function definition: `FUNCTION <name>(<params>) RETURNS <type> <statements> RETURN <value> ENDFUNCTION`; called without CALL as part of an expression.
Example procedure: `PROCEDURE Line(Size : INTEGER) ... ENDPROCEDURE` then `CALL Line(60)`.
Example function: `FUNCTION SumSquare(Number1 : INTEGER, Number2 : INTEGER) RETURNS INTEGER RETURN Number1×Number1 + Number2×Number2 ENDFUNCTION`; used as `OUTPUT SumSquare(10,20)`.

File Handling

Open file: `OPENFILE "FileA.txt" FOR READ` or `FOR WRITE`.
Read: `READFILE "FileA.txt", <variable>`; Write: `WRITEFILE "FileB.txt", <variable>`.
Close: `CLOSEFILE "FileA.txt"`.
A file can be opened in one mode at a time; WRITE creates a new file (overwrites existing).
Always close files when done.

Common Mistakes to Avoid (Recall Checklist)

Using `=` instead of `←` for assignment.
Lower-case keywords, or identifiers with underscores or leading lower-case.
Missing closing keywords: ENDIF, ENDWHILE, NEXT <identifier>, ENDCASE, ENDPROCEDURE, ENDFUNCTION.
Writing conditions in words ("x is greater than y") instead of symbols (`x > y`).
Using CALL on a function, or omitting CALL on a procedure call.
Declaring arrays without bounds, or indexing out of bounds.
Using variable/expression as constant value.
Forgetting separate OUTPUT prompt before INPUT.
Confusing REPEAT...UNTIL with WHILE...DO...ENDWHILE.
Using undeclared variables or wrong data types.

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1.Which of the following is the correct assignment operator in Cambridge 0478 pseudocode?
Easy
- A=
- B←
- C:=
- D→
2.In Cambridge 0478 pseudocode, keywords must be written in upper case (e.g., IF, THEN, ENDIF).
Easy
True or false?
3.Which of the following is the correct declaration of an integer variable named Counter?
Easy
- ADECLARE Counter : INTEGER
- BDECLARE Counter: Integer
- CINTEGER DECLARE Counter
4.In Cambridge 0478 pseudocode, identifiers may contain underscores (e.g., Total_Score).
Easy
True or false?
5.What is the value of MOD(10, 3) in Cambridge 0478 pseudocode?
Easy
- A3
- B1
- C0
- D3.33
6.A REPEAT...UNTIL loop always executes its body at least once.
Easy
True or false?
7.Which of the following is the correct way to declare a 1D array of 30 strings?
Medium
- ADECLARE StudentNames : ARRAY[1:30] OF STRING
- BDECLARE StudentNames : ARRAY[30] OF STRING
- CDECLARE StudentNames : ARRAY[1 TO 30] OF STRING
- DDECLARE StudentNames : ARRAY[1:30] STRING
8.A procedure must be called using the keyword CALL.
Easy
True or false?

Thêm câu hỏi

9.Match each loop construct to its correct closing keyword.
Medium
- FOR
- WHILE
- REPEAT
- NEXT
- ENDWHILE
- UNTIL
10.Arrange the following lines to correctly declare a constant and then use it in an assignment.
Easy
- CONSTANT Rate ← 10
- DECLARE Total : INTEGER
- Total ← Rate×5
11.Which of the following are valid declarations in Cambridge 0478 pseudocode? (Select all that apply)
Medium
- ADECLARE Score : INTEGER
- BDECLARE Name : STRING
- CDECLARE IsValid : BOOLEAN
- DDECLARE 2ndValue : INTEGER
- EDECLARE Total_Score : REAL
12.In Cambridge pseudocode, a comment must be preceded by // and can be placed on the same line as code.
Easy
True or false?
13.A student writes the following pseudocode. What is the output? DECLARE X : INTEGER X ← 5 IF X > 3 THEN OUTPUT "Big" ELSE OUTPUT "Small" ENDIF
Medium
- ABig
- BSmall
- CError
- DNothing
14.Which of the following correctly declares a 2D array of integers with 3 rows and 4 columns?
Hard
- ADECLARE Grid : ARRAY[1:3, 1:4] OF INTEGER
- BDECLARE Grid : ARRAY[1:4, 1:3] OF INTEGER
- CDECLARE Grid : ARRAY[3,4] OF INTEGER
- DDECLARE Grid : ARRAY[1:3][1:4] OF INTEGER
15.What is the purpose of the keyword CALL in Cambridge pseudocode?
Medium
- ATo call a procedure
- BTo call a function
- CTo declare a variable
- DTo output a value
16.In Cambridge pseudocode, arrays are indexed starting from 1 by default.
Medium
True or false?
17.Which of the following are valid ways to assign a value to a variable in Cambridge pseudocode? (Select all that apply)
Medium
- AX ← 5
- BX = 5
- CX ← X + 1
- DX ← 5.0
- EX ← "five"
18.A student writes the following pseudocode to input a number and output whether it is positive. Which line contains an error? 1 DECLARE Number : INTEGER 2 INPUT Number 3 IF Number > 0 4 THEN 5 OUTPUT "Positive" 6 ENDIF
Medium
- ALine 3: the condition should be Number ≥ 0
- BLine 5: the string should be in single quotes
- CLine 6: ENDIF is not needed because there is no ELSE
- DLine 2: INPUT should be followed by a prompt
19.Which of the following are valid uses of the built-in routines in Cambridge pseudocode? (Select all that apply)
Medium
- ALENGTH("Hello") returns 5
- BSUBSTRING("Hello", 2, 3) returns "ell"
- CUCASE("hi") returns "HI"
- DROUND(3.14159, 2) returns 3.14
- ERANDOM() returns a random integer between 1 and 6
20.In Cambridge pseudocode, the condition in a WHILE loop is tested at the top, so the body may be executed zero times.
Easy
True or false?
21.A program uses the following pseudocode. What is the output? DECLARE X : INTEGER X ← 5 IF X MOD 2 = 0 THEN OUTPUT "Even" ELSE OUTPUT "Odd" ENDIF
Medium
- AEven
- BOdd
- C5
- DNo output
22.In Cambridge pseudocode, the ELSE clause is indented by two spaces, while the statements inside the THEN clause are indented by four spaces.
Easy
True or false?
23.In Cambridge 0478 pseudocode, the keyword CONSTANT is written in upper case and the constant's value must be a literal, not a variable or expression.
Easy
True or false?
24.Which of the following correctly declares a constant named MaxScore with the value 100?
Medium
- ACONSTANT MaxScore ← 100
- BDECLARE MaxScore : CONSTANT ← 100
- CCONSTANT MaxScore = 100
25.In Cambridge 0478 pseudocode, keywords such as IF and WHILE must be written in upper case.
Easy
True or false?
26.Which of the following is the correct way to declare a constant named MaxScore with a value of 100 in Cambridge 0478 pseudocode?
Easy
- ACONSTANT MaxScore ← 100
- BDECLARE MaxScore CONSTANT ← 100
- CCONSTANT MaxScore = 100
- DMaxScore CONSTANT ← 100
27.Which of the following is the correct way to declare a 2D array of integers with 3 rows and 4 columns in Cambridge 0478 pseudocode?
Easy
- ADECLARE Grid : ARRAY[1:3, 1:4] OF INTEGER
- BDECLARE Grid : ARRAY[3][4] OF INTEGER
- CDECLARE Grid : ARRAY[1:3][1:4] OF INTEGER
- DDECLARE Grid : ARRAY[3,4] OF INTEGER
28.In Cambridge 0478 pseudocode, a function is called using the keyword CALL.
Easy
True or false?
29.In Cambridge 0478 pseudocode, a REPEAT...UNTIL loop may execute its body zero times if the condition is initially true.
Medium
True or false?
30.Which of the following are valid identifiers in Cambridge 0478 pseudocode? (Select all that apply)
Medium
- ATotalScore
- Btotal_score
- CTotalScore1
- D1TotalScore
- ETotal Score
31.Arrange the following lines to correctly declare an integer variable and then assign it the value 10.
Medium
- DECLARE Counter : INTEGER
- Counter ← 10
- OUTPUT Counter
32.Match each pseudocode construct to its correct closing keyword.
Easy
- IF
- WHILE
- CASE OF
- ENDIF
- ENDWHILE
- ENDCASE
33.In Cambridge 0478 pseudocode, the ELSE clause is indented by two spaces, while the statements inside the THEN clause are indented by four spaces.
Easy
True or false?
34.In Cambridge 0478 pseudocode, which of the following correctly declares a 2D array of integers with 3 rows and 4 columns?
Medium
- ADECLARE Grid : ARRAY[1:3, 1:4] OF INTEGER
- BDECLARE Grid : ARRAY[3:4] OF INTEGER
- CDECLARE Grid : ARRAY[1:3][1:4] OF INTEGER
- DDECLARE Grid : ARRAY[1:3, 1:4] OF INT
35.In Cambridge 0478 pseudocode, what is the keyword used to declare a constant?
Medium
- ACONST
- BCONSTANT
- CDECLARE CONSTANT
- DDEFINE
36.A student writes the following pseudocode to calculate the average of two numbers. The pseudocode contains an error. Which line contains the error? 1 DECLARE Num1 : REAL 2 DECLARE Num2 : REAL 3 DECLARE Average : REAL 4 INPUT Num1 5 INPUT Num2 6 Average ← (Num1 + Num2) / 2 7 OUTPUT Average
Medium
- ALine 1
- BLine 4
- CLine 6
- DLine 7
37.Which of the following correctly declares an array that can store the names of 50 students?
Medium
- ADECLARE StudentNames : ARRAY[1:50] OF STRING
- BDECLARE StudentNames[50] : STRING
- CDECLARE StudentNames : ARRAY[50] OF STRING
- DDECLARE StudentNames : ARRAY[0:49] OF STRING
38.A program uses the following pseudocode. What is the output? DECLARE X : INTEGER DECLARE Y : INTEGER X ← 10 Y ← 3 IF X > Y×3 THEN OUTPUT "A" ELSE OUTPUT "B" ENDIF
Medium
- AA
- BB
- CNo output
- DError
39.Which of the following are valid uses of the built-in routine SUBSTRING in Cambridge pseudocode? (Select all that apply)
Hard
- ASUBSTRING("Hello", 1, 3)
- BSUBSTRING("Hello", 0, 2)
- CSUBSTRING("Hello", 2, 3)
- DSUBSTRING("Hello", 1, 0)
- ESUBSTRING("Hello", 5, 1)
40.Arrange the following lines to correctly declare a procedure that outputs a line of dashes of a given length, then call it.
Medium
- CALL Line(10)
- END PROCEDURE
- PROCEDURE Line(Size : INTEGER)
- FOR Count ← 1 TO Size OUTPUT '-' NEXT Count
41.Complete the sentence.
Easy
The five basic data types in Cambridge 0478 pseudocode are INTEGER, REAL, CHAR, STRING and ____.
42.Complete the statement.
Easy
The built-in routine that returns the number of characters in a string is ____.
43.What is the value of DIV(17, 5) in Cambridge pseudocode?
Medium
44.Complete the pseudocode to output the numbers from 1 to 10.
Easy
FOR Count ← 1 TO 10 OUTPUT ____ NEXT Count
45.What is the keyword used to declare a constant in Cambridge pseudocode?
Easy
46.Using the pseudocode routine MOD, what is the value of MOD(17, 5)?
Medium
47.Complete the pseudocode to output the numbers from 10 down to 1.
Medium
FOR Index ← 10 TO 1 ____ -1 OUTPUT Index NEXT Index
48.What is the value of DIV(23, 5) in Cambridge 0478 pseudocode?
Easy
49.What is the keyword used to output data in Cambridge 0478 pseudocode?
Easy
50.Complete the pseudocode declaration statement.
Easy
DECLARE Score : ____
51.What is the value of LENGTH("Computer Science") in Cambridge 0478 pseudocode?
Easy
52.Complete the pseudocode to declare a constant named MaxSize with value 100.
Easy
____ MaxSize ← 100
53.Explain why the following pseudocode will not work as intended. Rewrite it correctly. CONSTANT MaxSize ← 10 DECLARE Size : INTEGER Size ← MaxSize + 5 MaxSize ← Size
Hard
54.Explain why the following pseudocode will not work as intended and rewrite it correctly. CONSTANT MaxSize ← 10 DECLARE Size : INTEGER Size ← MaxSize + 5 MaxSize ← 20
Medium
55.Explain why the following pseudocode will not work as intended and rewrite it correctly. CONSTANT MaxSize ← 10 DECLARE Size : INTEGER Size ← MaxSize + 5 MaxSize ← 20 OUTPUT Size
Hard
56.What is the value of DIV(17, 5) in Cambridge pseudocode?
Medium
- A4
- B2
- C3
- D5
57.Using the pseudocode routine MOD, what is the value of MOD(17, 5)?
Medium
- A4
- B2
- C3
- D1
58.What is the value of DIV(23, 5) in Cambridge 0478 pseudocode?
Easy
- A6
- B3
- C4
- D5
59.What is the value of LENGTH("Computer Science") in Cambridge 0478 pseudocode?
Easy
- A18
- B15
- C16
- D17

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## 0478 Pseudocode from Memory — Night-Before Notes **Why it matters:** Paper 2 (1h45, 75 marks) requires pseudocode answers. Programming languages earn no marks (except the final 15-mark scenario). Mark schemes use Cambridge pseudocode — half-remembering loses marks. **Style rules** - Keywords UPPER CASE: IF, THEN, ELSE, ENDIF, REPEAT, UNTIL, WHILE, DO, ENDWHILE, FOR, NEXT, CASE OF, OTHERWISE, ENDCASE, DECLARE, CONSTANT, INPUT, OUTPUT, PROCEDURE, ENDPROCEDURE, CALL, FUNCTION, RETURNS, RETURN, ENDFUNCTION, OPENFILE, READFILE, WRITEFILE, CLOSEFILE, ARRAY, OF, STEP. - Identifiers Pascal case (e.g., NumberOfPlayers), letters/digits only, start with capital, no underscores. Case-insensitive (Countdown = CountDown). - Indentation: 4 spaces per block; 2 spaces for THEN/ELSE and CASE clauses. - Comments: // ... **Data types & declarations** - Types: INTEGER, REAL, CHAR, STRING, BOOLEAN. - Literals: reals need digit both sides (4.7, 0.0); CHAR in single quotes ('x'); STRING in double quotes ("..."); Booleans TRUE/FALSE. - DECLARE <id> : <type> - CONSTANT <id> ← <literal> (only literal, never variable/expression). **Assignment & operators** - Use ←, not =. - Arithmetic: + - * / ^; DIV(x,y) quotient (discard fraction), MOD(x,y) remainder. - Relational: = < <= > >= <> - Logical: AND OR NOT (BOOLEAN operands). **Input/Output** - INPUT <var> (no prompt inside; use OUTPUT before). - OUTPUT can take multiple comma-separated values. **Selection** - IF <cond> THEN ... ENDIF / ELSE ... ENDIF (2-space indent for THEN/ELSE). - CASE OF <id>: <value> : <statement> ... OTHERWISE <statement> ENDCASE (first match runs; OTHERWISE last). **Iteration** - FOR <id> ← <start> TO <end> ... NEXT <id> (inclusive; STEP optional; counter INTEGER). - REPEAT ... UNTIL <cond> (post-condition, runs at least once). - WHILE <cond> DO ... ENDWHILE (pre-condition, may run zero times). **Arrays** - DECLARE <id> : ARRAY[<lower>:<upper>] OF <type> (state lower bound, usually 1). - Index with [i] or [i,j]. Fill with loop. **String/library routines** - LENGTH(string), SUBSTRING(string, start, length), UCASE, LCASE, ROUND(real, places), RANDOM() (0–1 inclusive). **Procedures & functions** - PROCEDURE <name>(params) ... ENDPROCEDURE; call with CALL. - FUNCTION <name>(params) RETURNS <type> ... RETURN <value> ENDFUNCTION; call without CALL in expression. **File handling** - OPENFILE "file" FOR READ/WRITE; READFILE/WRITEFILE "file", var; CLOSEFILE "file". WRITE overwrites. **Top 10 marks thrown away** 1. = instead of ← 2. Lower-case keywords or bad identifiers 3. Missing ENDIF/ENDWHILE/NEXT/ENDCASE/ENDPROCEDURE/ENDFUNCTION 4. Conditions in words not symbols 5. CALL on function or missing CALL on procedure 6. Array without bounds or out-of-range index 7. CONSTANT with variable/expression 8. No OUTPUT prompt before INPUT 9. Confusing REPEAT...UNTIL with WHILE...DO...ENDWHILE 10. Undeclared variable or wrong type

Pseudocode: A structured way of writing algorithms using English-like statements; in CIE 0478 it must follow specific conventions (keywords upper case, assignment arrow ←, etc.).
Assignment operator: The left arrow ← used to assign a value to a variable, e.g., Counter ← 0. Not the equals sign.
Pascal case: Identifiers with each word starting with a capital letter, e.g., NumberOfPlayers. No underscores, start with capital letter.
DECLARE: Statement to declare a variable with its data type, e.g., DECLARE Counter : INTEGER.
CONSTANT: Statement to define a constant with a literal value, e.g., CONSTANT HourlyRate ← 6.50. Value must be a literal.
DIV: Integer division routine: DIV(x, y) returns the quotient with fractional part discarded, e.g., DIV(10,3) = 3.
MOD: Modulo routine: MOD(x, y) returns the remainder of integer division, e.g., MOD(10,3) = 1.
CASE OF: Selection statement that tests an identifier against multiple values, executing the first matching branch; OTHERWISE optional and last.
FOR...NEXT: Count-controlled loop: FOR <id> ← <start> TO <end> ... NEXT <id>. Counter is INTEGER, inclusive, optional STEP.
REPEAT...UNTIL: Post-condition loop: body executes at least once, condition tested at the bottom.
WHILE...DO...ENDWHILE: Pre-condition loop: condition tested at the top, body may execute zero times.
PROCEDURE: A named block of code that performs a task; called with CALL. Declared with PROCEDURE ... ENDPROCEDURE.
FUNCTION: A named block that returns a single value; declared with FUNCTION ... RETURNS <type> ... RETURN ... ENDFUNCTION. Called without CALL in an expression.
ARRAY: Fixed-length structure holding elements of one data type, accessed by index. Declared with bounds, e.g., ARRAY[1:30] OF STRING.
OPENFILE: Opens a file for reading or writing: OPENFILE "filename" FOR READ/WRITE.
READFILE: Reads a line from an open file into a variable: READFILE "filename", variable.
WRITEFILE: Writes a value to an open file: WRITEFILE "filename", value.
CLOSEFILE: Closes an open file: CLOSEFILE "filename".
LENGTH: Built-in function returning the number of characters in a string, e.g., LENGTH("Happy Days") = 10.
SUBSTRING: Built-in function returning a substring: SUBSTRING(string, start, length), e.g., SUBSTRING("Happy Days",1,5) = "Happy".
UCASE/LCASE: Built-in functions converting a string/char to upper/lower case, e.g., UCASE("Happy") = "HAPPY".
ROUND: Built-in function rounding a REAL to a given number of decimal places: ROUND(identifier, places).
RANDOM: Built-in function returning a random number between 0 and 1 inclusive.

Thẻ ghi nhớ

What is the assignment operator in Cambridge 0478 pseudocode?

The left arrow ←, e.g., Counter ← 0. An equals sign is only for equality in conditions.

How are keywords and identifiers formatted in 0478 pseudocode?

Keywords are in UPPER CASE (IF, THEN, ENDIF, etc.). Identifiers use Pascal case (e.g., NumberOfPlayers) and must start with a capital letter, containing only letters and digits, no underscores.

List the five basic data types in 0478 pseudocode.

INTEGER, REAL, CHAR, STRING, and BOOLEAN.

How do you declare a variable and a constant?

Variable: DECLARE <identifier> : <data type>. Constant: CONSTANT <identifier> ← <literal value>.

What is the rule for the value of a CONSTANT?

It must be a literal only – never a variable, another constant, or an expression.

How do you write a comment in 0478 pseudocode?

Start with // and run to the end of the line. For multi-line comments, repeat // on each line.

What is the correct syntax for an IF statement with an ELSE clause?

IF <condition> THEN <statements> ELSE <statements> ENDIF, with THEN/ELSE clauses indented two spaces.

What is the correct syntax for a CASE statement?

CASE OF <identifier> <value> : <statement> ... OTHERWISE <statement> ENDCASE. OTHERWISE must be last.

What is the correct syntax for a FOR loop?

FOR <identifier> ← <value1> TO <value2> ... NEXT <identifier>. The counter must be an INTEGER variable.

What is the correct syntax for a REPEAT loop?

REPEAT <statements> UNTIL <condition>. The condition is tested at the bottom, so the body always runs at least once.

What is the correct syntax for a WHILE loop?

WHILE <condition> DO <statements> ENDWHILE. The condition is tested at the top, so the body may run zero times.

How do you declare a 1D array and a 2D array?

DECLARE <identifier> : ARRAY[lower:upper] OF <data type>. For 2D: ARRAY[lower1:upper1, lower2:upper2] OF <data type>. Lower bound should be explicit, usually 1.

What is the syntax for a PROCEDURE and how do you call it?

PROCEDURE <name>(<parameters>) ... ENDPROCEDURE. Call it with CALL <name>(<arguments>).

What is the syntax for a FUNCTION and how do you call it?

FUNCTION <name>(<parameters>) RETURNS <data type> ... ENDFUNCTION. Call it without CALL, as part of an expression.

What are the built-in string routines and their purposes?

LENGTH(<string>) returns length; SUBSTRING(<string>, start, length) returns substring; UCASE(<string>) converts to uppercase; LCASE(<string>) converts to lowercase.

What do ROUND and RANDOM do?

ROUND(<real>, <places>) rounds a REAL to a given number of decimal places. RANDOM() returns a random number between 0 and 1 inclusive.

What do DIV and MOD return?

DIV(<x>, <y>) returns the integer quotient with fractional part discarded. MOD(<x>, <y>) returns the remainder. Both operands are integers.

What is the correct syntax for file operations?

OPENFILE "filename" FOR READ/WRITE, READFILE "filename", <variable>, WRITEFILE "filename", <value>, CLOSEFILE "filename".

How do you write a condition correctly?

Use relational operators: =, <, ≤, >, ≥, <>. Write x > y, never "x is greater than y".

What is the indentation rule for blocks and THEN/ELSE/CASE clauses?

Lines inside a block are indented four spaces. THEN/ELSE and CASE clauses are indented two spaces.

What are the common mistakes that lose marks in pseudocode?

Using = for assignment, lower-case keywords, missing closing keywords, writing conditions in words, using CALL on functions, omitting array bounds, using non-literal constants, missing OUTPUT prompt, confusing REPEAT/WHILE, and using undeclared variables.

What is the rule for identifiers regarding case sensitivity?

Identifiers are case insensitive, so Countdown and CountDown are the same variable and must not be used as two different variables.

What is the syntax for INPUT and OUTPUT?

INPUT <variable> takes a single variable. OUTPUT <value1>, <value2>, ... can take multiple comma-separated values. Prompts are separate OUTPUT statements before INPUT.

What is the rule for single-letter identifiers?

Single letters are acceptable only where conventional: i and j for array indices, X and Y for coordinates.

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