Integers & Pattern Matching— Homework 1 Solution

Description

• Integers

• 1. Define the function dollar2won, which consumes an integer number of dollars and produces the won equiv-alent. Use the won/dollar conversion rate of 1100 won per dollar.

• 2. Write the function volumeOfCuboid, which consumes three integer numbers denoting lengths of three sides and produces the volume of the cuboid.

• 3. Write the function isEven, which consumes an integer number and returns whether the number is even.

• 4. Write the function isOdd, which consumes an integer number and returns whether the number is odd.

• 5. Write the function gcd, which consumes two integer numbers and returns the greatest common divisor of them.

• 6. Write the function lcm, which consumes two integer numbers and returns the least common multiple of them.

• Pattern Matching

You have a type COURSE, which is either CS320, CS311, or CS330. CS320 has two members: quiz for a number

of quizzes and homework for a number of programming assignments. CS311 has one member: homework which

is a number too. CS330 has two members: projects for a number of projects and homework for a number of programming assignments.

trait COURSE

case class CS320(quiz: Int, homework: Int) extends COURSE

case class CS311(homework: Int) extends COURSE

case class CS330(projects: Int, homework: Int) extends COURSE

1. Define the function numOfHomework, which consumes a course and produces the number of programming assignments for the given course.

2. Define the function hasProjects, which consumes a course and produces true only when the given course is CS330 with more than or equal to two projects, otherwise produces false.

• List

• 1. Define the function namePets, which consumes a list of pets and produces a corresponding list of pets with names; it names all occurrences of dog with happy, cat with smart, pig with pinky, and keeps the other pets as unnamed. For example,

namePets(List(“dog”, “tiger”, “cat”)) == List(“happy”, “tiger”, “smart”)

2. Generalize namePets to the function giveName. The new function consumes two strings, called old and new. It produces a function that gets a list of strings and replaces all occurrences of old by new in the list. For example,

namePets(List(“dog”, “tiger”, “cat”)) == List(“happy”, “tiger”, “smart”) val nameBears: List[String] => List[String] = giveName(“bear”, “pooh”) nameBears(List(“pig”, “cat”, “bear”)) = List(“pig”, “cat”, “pooh”)

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