Thinking Ahead

• What does designing a solution entail in the context of computational problems?


  It involves thinking ahead about the different components of a problem and how they will be handled.
• Why is it important for developers to consider difficulties that may arise when software is used?

  To design strategies that make programs easy and intuitive to use.
• What are the two main components of all computational problems?

  Inputs and outputs.
• What are inputs in the context of computational problems?

  Any data required to solve the problem, entered into the system by the user.
• What are outputs in computational problems?

  Results that are passed back once the inputs have been processed and the problem solved.
• What must designers decide on to present a solution effectively?

  A suitable data type, structure, and method.
• In the context of an ATM program, what input is required for a balance check?

  Card details and PIN entered via keypad.
• What output is displayed if a deposit is selected in an ATM program?

  Total amount entered on screen.
• What happens when a withdrawal is selected in an ATM program?

  The correct amount of cash is dispensed.
• What devices are required to capture input data for an ATM?

  A touch screen, magnetic stripe card reader, and keypad.
• What devices are used to output data from an ATM?

  A monitor, cash dispenser, printer, and speakers.
• What is the typical first step for designers when creating a solution?

  Considering what outputs are required based on the user’s requirements.
• What are preconditions in programming?


  Requirements that must be met before a program can be executed.
• How can preconditions be specified in programming?


  They can be tested within the code or included in the documentation.
• What does the function pop() do in a stack?

  It removes the last item added to the stack.
• Why is it important to check that a stack is not empty before using pop()?

  To avoid errors that could cause the program to crash.
• What is the responsibility of the user regarding preconditions specified in documentation?

  To ensure inputs meet the requirements specified.
• How do preconditions contribute to program efficiency?

  They reduce the length and complexity of the program and save time needed for debugging.
• What are reusable program components?

  Commonly used functions packaged into libraries for reuse.
• What is the benefit of using reusable components in software development?

  They are more reliable as they have already been tested.
• What is the process of decomposing a problem in software design?

  Breaking it down into smaller, simpler tasks.
• What is caching in computing?

  The process of storing instructions or values in cache memory after they have been used.
• What is the purpose of caching?

  To save time retrieving instructions from secondary storage again.
• What is prefetching in the context of caching?

  Algorithms predict which instructions are likely to be used soon and load them into cache beforehand.
• What is a limitation of prefetching?

  The accuracy of the algorithms used to predict instructions.
• How does cache size affect caching performance?

  Larger caches take longer to search, limiting how much data can be stored effectively.
• What is the general challenge of implementing caching effectively?

  It can be difficult to implement but can significantly improve performance if done correctly.
• What are the key components of inputs and outputs in a computational problem?

  • Inputs: Data required to solve the problem, entered by the user.
  • Outputs: Results passed back after processing the inputs.
• What are the steps involved in designing a solution for a computational problem?

  1. Identify required outputs based on user requirements.
  2. Determine necessary inputs.
  3. Process inputs to achieve outputs.
• What are the advantages and disadvantages of using reusable components in software development?

  Advantages:

  • More reliable due to prior testing.
  • Saves time, money, and resources.
  • Can be reused in future projects.

  
  

  Disadvantages:

  • Compatibility issues may arise.
  • Modifications may be costly and time-consuming.