Recursion and Programming

• What is a global variable?

  Visible throughout a program
• What is a local variable?

  Visible only in its module
• Why are global variables sometimes used?

  To access the same value from various parts
• Why is it good practice to avoid global variables?

  They increase program complexity and conflicts
• What does branching/selection do in programming?

  Decides which code is run
• What is iteration in programming?

  Repeatedly runs the same code
• What is sequence in programming?

  Instructions performed one after another
• What are the differences between a procedure and a function?

  • A function returns a single value.
  • A procedure does not return a value.
  • A function is part of an expression.
  • A procedure is an instruction/statement.
• What happens when a procedure is called?

  The code in the procedure executes
• What is parameter passing by value?

  Uses a local copy of the data
• What is parameter passing by reference?

  Memory location of data is sent
• What are the habits for writing good functions?

  • No longer than a single page of code.
  • Variable identifiers must conform to a standard.
  • Each function must have a single entry point.
  • Variables must not be set up outside the function's scope.
• What is a stack in programming?

  LIFO data structure
• What is a queue in programming?

  FIFO data structure
• How does a stack operate?

  Data is popped/pushed from the top
• How does a queue operate?

  Data is dequeued from the front
• What is an array?

  Fixed size data structure
• What is a list in programming?

  Dynamic size data structure
• What is a tuple?

  Immutable data structure with multiple types
• What is a linked list?

  Ordered set of data elements linked together
• What is a tree in programming?

  Hierarchical structure with nodes
• What is the root node in a tree?

  The topmost node in the hierarchy
• What are leaf nodes in a tree?

  Nodes without any lower nodes
• How do you search a binary tree?

  Check root, then left or right subtree
• What is a recursive algorithm?

  One that calls itself
• What is the factorial of 5?

  $120$
• What is the base case in recursion?

  Condition that stops the recursion
• What is the advantage of iteration over recursion?

  Uses fewer variables and memory
• Why does recursion use more memory than iteration?

  Each call stores state on the stack
• What are the advantages of recursion over iteration?

  • Expresses problems naturally.
  • Simplifies complex problems.
  • Easier to implement for certain algorithms.