Variables, constants, data types, sequence, selection, iteration, subprograms. Pseudocode questions and trace tables require these.
—
Best score
—
Last attempt
Best attempt progress
0
XP earned
Watch first — Craig 'n' Dave
Craig 'n' Dave · Edexcel 1CP2Programming Constructs
Key facts
Core constructs — fill in the table
Term
Description
Sequence
Selection
Iteration
Variables
Constants
Exam wording (constants)
Advantages of constants
Less likely to be accidentally changed → more robust programs
If the value needs updating, only ONE change needed (where the constant is defined)
Makes code easier to read — a meaningful name is more readable than a "magic number"
Example: MAX_SPEED = 70 is clearer than using 70 throughout the code
Input validation and error types — fill in the table
Error type
Description
Syntax error
Runtime error
Logic error
Exam wording (syntax error)
Boolean values
Exam questions — 4 questions · 12 marks · from real 1CP2 past papers
1 markSyntax error1CP2 Jun 2024 Q1(d)(i) style
What is a syntax error?
A A program that runs but produces the wrong answer
B A program that crashes when dividing by zero
C Code that violates the grammar or rules of the programming language
D A variable that contains the wrong data type
1 markConstant vs variable1CP2 Specimen Q5(c) style
Why should a programmer use a constant instead of a variable to store the value of pi (3.14159)?
A Constants are stored faster by the CPU
B Constants use less memory than variables
C Pi should never change during the program — using a constant prevents accidental modification and if the value ever needs updating, only one change is required
D Variables cannot store decimal numbers
4 marksDescribe iteration types1CP2 style
Describe the difference between a FOR loop and a WHILE loop. Give an example situation where each would be most appropriate. (4 marks)
Hint: Cover: how each loop is controlled (count vs condition) + when each is appropriate. Two marks per loop type.
+40 XP
4 marksError type identification1CP2 Jun 2024 Q1(d)(ii) style
A program contains the following code: result = 10 / userInput
Explain what type of error occurs if the user enters 0, and why the program behaves as it does. (2 marks — linked)
Hint: Name the error type (runtime) AND explain WHY — what makes this impossible for the CPU to execute.