Paper 2 Strategies: Reading and Writing Pseudocode in OCR Reference Language

OCR J277 Paper 2 requires you to read, write, and trace code. OCR provides a reference language (pseudocode) that appears in exam questions. You must be familiar with its syntax. This lesson covers the key constructs of OCR pseudocode and strategies for answering code-based questions.

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OCR Reference Language Syntax

The OCR reference language is a pseudocode that looks similar to Python but has some differences. You can answer Paper 2 questions using either OCR pseudocode or a high-level language like Python. However, you must understand OCR pseudocode because the exam questions use it.

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Variables and Assignment

// OCR pseudocode
name = "Alice"
age = 16
score = 0.0
isStudent = true

# Equivalent Python
name = "Alice"
age = 16
score = 0.0
is_student = True

Key difference: OCR pseudocode uses lowercase true and false.

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Input and Output

// OCR pseudocode
name = input("Enter your name: ")
print("Hello " + name)

# Equivalent Python
name = input("Enter your name: ")
print("Hello " + name)

These are essentially identical in OCR pseudocode and Python.

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Selection (If Statements)

// OCR pseudocode
if score >= 50 then
    print("Pass")
elseif score >= 40 then
    print("Near miss")
else
    print("Fail")
endif

# Equivalent Python
if score >= 50:
    print("Pass")
elif score >= 40:
    print("Near miss")
else:
    print("Fail")

OCR pseudocode	Python
if ... then	if ...:
elseif	elif
endif	(indentation ends the block)

OCR Exam Tip: In OCR pseudocode, every if must have a matching endif. Every for must have a matching next. Every while must have a matching endwhile. Missing these closing keywords will lose marks.

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Iteration: For Loops

// OCR pseudocode
for i = 1 to 10
    print(i)
next i

# Equivalent Python
for i in range(1, 11):
    print(i)

Key difference: OCR for i = 1 to 10 includes both 1 and 10. Python range(1, 11) includes 1 but excludes 11. The result is the same.

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Iteration: While Loops

// OCR pseudocode
password = ""
while password != "secret"
    password = input("Enter password: ")
endwhile
print("Access granted")

# Equivalent Python
password = ""
while password != "secret":
    password = input("Enter password: ")
print("Access granted")

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Iteration: Do-While (Repeat-Until)

// OCR pseudocode
do
    password = input("Enter password: ")
until password == "secret"
print("Access granted")