tech final review

• Algorithm


  A step-by-step set of instructions to accomplish a task, whether by a computer or a human
• Algorithm


  • Provides a sequence of steps (instructions) to follow in order to achieve the desired outcome
  • As long as it resolves the problems at hand, it can be valuable
• Data types in App Inventor

  • Numbers
  • Text (strings)
  • Boolean values
  • Objects
• List


  A collection of elements
• List in a computer program

  • List of student names in a classroom management app
• Loop


  Used when you know exactly how many times you need to iterate through a block of code
• While loop


  Used when you are uncertain about the number of iterations required or when the loop should continue until a certain condition is met
• Big O notation


  A way of expressing the time complexity of an algorithm in terms of the growth rate of the algorithm's resource usage (usually time or memory) as the size of the input data increases
• Common Big O notation classifications


  • O(1)
  • O(log n)
  • O(n)
  • O(n^2)
  • O(2^n)
• O(1)


  Considered okay
• O(2^n)


  Considered unacceptable because of its exponential growth rate
• Linear search


  Sequentially checks each element of the list until it finds the target element or reaches the end of the list
• Worst-case scenario for linear search


  • Occurs when the target element is not present in the list, requiring n comparisons, where n is the number of elements in the list
• Binary search


  Repeatedly divides the search interval in half until the target element is found or the interval is empty
• Worst-case scenario for binary search

  • Occurs when the target element is not present in the list, requiring log2(n) comparisons, where n is the number of elements in the list
• Downside of binary search


  List must be sorted beforehand, which can be an additional overhead
• Sorting


  The process of arranging items in a systematic order, usually either increasing or decreasing
• Benefits of sorting


  • Can make searches more efficient
  • Can facilitate other operations such as data retrieval & analysis
• Quicksort


  Works by selecting a pivot element from the list & partitioning the other elements into 2 sub-lists according to whether they are less than or greater than the pivot
• Selection sort


  Works by repeatedly finding the minimum element from the unsorted part of the list & moving it to the beginning
• Volatile memory


  Loses its data when the power is turned off
• Non-volatile memory


  Retains its data even when the power is turned off
• Volatile memory

  • RAM
• Non-volatile memory


  • ROM, hard drives
• CPU (Central Processing Unit)

  The "brain" of the computer responsible for executing instructions
• Main parts of the CPU

  • Control Unit
  • Arithmetic Logic Unit (ALU)
• Control Unit


  Coordinates the activities of the CPU
• Arithmetic Logic Unit (ALU)


  Performs arithmetic & logical operations
• Software


  The electronic instructions that govern a computer's actions to provide a computing service
• Categories of software


  • System software (operating systems, utility programs)
  • Application software (word processors, web browsers)
• System software


  Controls and manages computer hardware & provides a user interface
• Types of system software

  • Operating system (OS)
  • Utility programs
• Jobs/responsibilities of an operating system

  • Controls computer hardware
  • Manages RAM & processor
  • Manages programs
  • Monitors performance
  • Controls input/output devices
  • Stores & manages files
  • Provides a user interface
• The 2 basic components that make up all computers are CPU and RAM
• RAM


  Stores data while being used by the processor
• ROM


  Read Only Memory; permanent storage for data and instructions that do not change
• CPU


  Performs arithmetic and logical operations
• Categories of software

  • System software
  • Application software
  • Programming software
  • Hardware software
• Functions of an operating system

  • Provide a user interface
  • Manage RAM
  • Manage programs
  • All of the above - answer
• Compiler


  Converts high-level language into machine-level language