Paper 2 Exam Preparation Lecture

May 30, 2024

Review flashcards

Paper 2 Exam Preparation Lecture

Introduction

  • Comprehensive coverage of Paper 2 topics and potential exam questions.
  • Aim: By the end, you will have a good understanding and hopefully enjoy Paper 2.

1. Computational Thinking

  • Decomposition: Breaking a problem into smaller sub-problems to tackle individually.
  • Abstraction: Removing unnecessary details to focus on important details.
  • Algorithmic Thinking: Deciding on the order of instructions and identifying decisions.

Example Question

  • Scenario: Elliot wants to create a program to store football match results and goal scorers.
  • Abstraction: Removing unnecessary details and focusing on key details (e.g., using only surnames).

2. Designing, Creating, and Refining Algorithms

  • Tools: Flowcharts, Trace Tables, and Pseudocode.
  • Importance of knowing your symbols (e.g., for exams).

Flowchart Example

  • Scenario: Fast food restaurant offering half-price meals to students or discount cardholders on non-Saturdays.
  • Basic flowchart structure with input, decision diamonds, and action outputs.

Trace Table Example

  • Scenario: Given initial values, increment and decrement based on conditions.

3. Searching and Sorting Algorithms

  • Covered more in-depth in a separate video.

Quick Recap on Sorting and Searching

  • Linear Search: Sequentially checking each item in an array.
    • Pros: No precondition needed.
    • Cons: Checks every item (inefficient).
  • Binary Search: Finding an item in a sorted list by repeatedly dividing the search interval in half.
    • Pros: Very efficient with large sorted lists.
    • Cons: Requires the list to be sorted.

Sorting Algorithms

  • Bubble Sort: Comparing pairs and swapping if in the wrong order.
    • Keywords: Pairs, Swapping.
  • Insertion Sort: Placing each element in its correct position in the sorted list.
  • Merge Sort: Dividing the list into sublists and merging back in order using divide and conquer approach.

4. Programming Fundamentals

  • Variables and Constants: Changing values during execution (variables) vs unchangeable values (constants).
  • Programming Constructs: Sequence, Selection, Iteration.

Data Types

  • Integer: Whole numbers.
  • Real/Float: Decimal numbers.
  • Boolean: True or False values.
  • Character: Single character.
  • String: Collection of characters.
  • Casting: Converting data types.

5. Additional Programming Techniques

  • String Manipulation: Slicing, Concatenation, Length, Substrings.
  • File Handling: Open, Read, Write, Close files.
  • SQL Commands: Select, From, Where.
  • Arrays: One-dimensional and Two-dimensional arrays.

Subprograms

  • Types: Procedures (no return value), Functions (returns a value).
  • Local and Global Variables: Scope and access differences.
  • Benefits of Subprograms: Readability, maintainability, reuse.

6. Producing Robust Programs

  • Defensive Design: Anticipating issues and defending against them.
    • Anticipating Misuse: Preventing user errors.
    • Authentication: Verifying user identity.
    • Input Validation: Ensuring inputs meet criteria.
  • Maintainability: Using subprograms, proper variable names, indentation, and comments.

Testing

  • Testing Types: Iterative (during development), Terminal (final testing).
  • Error Types: Syntax (grammatical), Logic (logical issues).
  • Testing Data: Normal, Boundary, Invalid, Erroneous.

7. Boolean Logic

  • NOT Gate: Inverts input (0 to 1, 1 to 0).
  • AND Gate: Output 1 only if both inputs are 1.
  • OR Gate: Output 1 if either input is 1.

Example Question

  • Flood light system using motion and light sensors to decide activation.
  • Logic Requirements: Understanding of Boolean Gates.

8. Programming Languages and IDEs

  • Low-Level Languages: Machine code, Assembly language (hardware dependent).
  • High-Level Languages: Python, Java, etc. (hardware independent).
  • Translators: Compilers and Interpreters differences.

Compiler vs Interpreter

  • Compilers: Translate entire program, produces executable file.
  • Interpreters: Translate and run line by line, no executable file.

Integrated Development Environment (IDE)

  • Features: Editor, Error Diagnostics, Runtime Environment, Translators.

Conclusion

  • Review and application of robust techniques are crucial for success in Paper 2.
  • Practice, understand key concepts and you will excel.

Best of luck in your exams!