Recursive Programming in Scheme

These flashcards cover key concepts and definitions related to recursive programming in Scheme, including various list operations and procedures.

What is recursion in programming?

Recursion is the process of defining a function in terms of itself, allowing for repeated application of the same procedure.

What does the 'car' function do in Scheme?

The 'car' function returns the first element of a list.

What does the 'cdr' function do in Scheme?

The 'cdr' function returns the rest of the list after removing the first element.

What can recursion be used for in arithmetic operations?

Recursion can be used to perform arithmetic by breaking down operations into smaller, repeatable processes, such as addition.

What is a base case in recursion?

A base case is a condition under which a recursive function stops calling itself, preventing infinite loops.

How do you sum a list of numbers recursively in Scheme?

By taking the first element (car) and adding it to the sum of the rest of the list (cdr) recursively.

What is the 'append' operation in Scheme?

The 'append' operation combines two lists into one, linking their elements.

What is the purpose of the 'null' check in list procedures?

To determine if the list is empty, which is typically the base case for recursive functions.

Describe the structure for a typical recursive list procedure in Scheme.

It generally involves a base case check, then performing an operation on the car of the list, and a recursive call on the cdr.

What is the result of adding zero to any number using recursion?

Adding zero to any number returns that number, as zero does not affect the sum.

How can you create a new list containing the squares of elements in another list?

By recursively taking each element, squaring it, and combining it with the recursion result on the rest of the list.

What is a lambda function in Scheme?

A lambda function is an unnamed procedure that can be used for defining functions without assigning a name.

How can you check if a list is non-empty in Scheme?

By checking if the list is not null.

What does the 'cons' function do in Scheme?

The 'cons' function constructs a new pair or list by adding an element to the front of an existing list.

What happens when you apply a function to a 'null' list in Scheme?

It typically returns a predefined value, often zero or an empty list, depending on the function.

How is the 'duplicate list' procedure designed in Scheme?

By recursively consing the car of the list twice onto the result of a recursive call on the cdr.

What is the purpose of recursive comparison in lists?

To check whether two lists have the same structure, iterating through each sub-list and comparing their lengths.

In what scenario would you return an error in a list procedure?

If a non-list argument is passed to a procedure expecting a list.

How do you handle cases where two lists have different lengths in recursive addition?

By returning the longer list after summing the elements up to the shorter list's length.

What does the function 'remember' do in Scheme?

It removes the first occurrence of an element from a list.

How do you create a list of numbers from one to a specified maximum in Scheme?

By using a recursive function that adds each successive number until it reaches the maximum.