Key Concepts and Syntax Glossary

Below are key concepts and the syntax used in OCR Exam Reference Language, based on Python. This reference language is simplified for use in exams to help focus on logic and problem-solving without needing external libraries or complex syntax.

Operators

Type	Symbols	Description
Comparison	`==`, `!=`, `<`, `<=`, `>`, `>=`	Used to compare values.
Arithmetic	`+`, `-`, `*`, `/`, `^`, `MOD`, `DIV`	Basic mathematical operations like addition, subtraction, multiplication, division, exponentiation, modulo, and integer division.
Boolean	`AND`, `OR`, `NOT`	Logical operators are used in conditions.

Variables and Input/Output

Concept	Keywords/Symbols	Example
Assignment	`=`	`x = 3`
Input	`input(…)`	`name = input("Enter name")`
Output	`print(…)`	`print("Hello " + name)`
Constants	`const`	`const vat = 0.2`
Global Variables	`global`	`global userID = "Cust001"`

Iteration (Loops)

Type	Keywords/Symbols	Example
FOR loop	`for … to …`, `next …`	`for i = 0 to 9` `print(i)` `next i`
WHILE loop	`while … endwhile`	`while answer != "Yes"` `answer = input("New answer")` `endwhile`
DO UNTIL loop	`do … until …`	`do` `answer = input("New answer")` `until answer == "Yes"`

Selection (Conditions)

Concept	Keywords/Symbols	Example
IF-THEN-ELSE	`if … then`, `elseif … then`, `else`, `endif`	`if x > 10 then` `print("Large")` `else` `print("Small")` `endif`
CASE/SWITCH	`switch … case …`, `default`, `endswitch`	`switch day:` `case "Sat": print("Saturday")` `case "Sun": print("Sunday")` `default: print("Weekday")` `endswitch`

String Handling

Concept	Keywords/Symbols	Example
Length	`.length`	`subject.length` returns 15
Substring	`.substring(x, i)`	`subject.substring(3,5)` returns "put"
Concatenation	`+`	`print("Hello " + name)`
Uppercase/Lowercase	`.upper`, `.lower`	`subject.upper()` returns "HELLO"

Arrays

Concept	Keywords/Symbols	Example
Array Declaration	`array …`	`array colours[5]`
2D Array Declaration	`array … […,…]`	`array gameboard[8,8]`
Array Assignment	`array[…]=…`	`gameboard[1,0] = "Pawn"`

Subprograms

Concept	Keywords/Symbols	Example
Procedure	`procedure name(…)`, `endprocedure`	`procedure greet()` `print("Hello")` `endprocedure`
Function	`function name(…)`, `return`	`function squared(number)` `return number^2` `endfunction`

File Handling

Concept	Keywords/Symbols	Example
Open File	`open(…)`	`myFile = open("file.txt")`
Read Line	`.readLine()`	`myFile.readLine()`
Write Line	`.writeLine(…)`	`myFile.writeLine("Add this line")`
Close File	`.close()`	`myFile.close()`

Key Concepts and Syntax Glossary Simplified Revision Notes for GCSE OCR Computer Science