Work 07: Searching for Truth

Posted: Fri Sep 19

Due: Monday 9/22 10:00am

Submission name: work07.rkt

Chapter 5 covers boolean values and operators.

Write contracts and the functions for the following:

Use define and lambda to write your functions. Include test cases with descriptive output.

• isBetween
  • Takes 3 numbers as inputs (let’s call them a, b and c)
  • Returns:
    • true if a is greater than b and a is less than c
    • false in all other cases
  • Examples:

    (isBetween 5 4 6) ==> true
    (isBetween 3 7 9) ==> false
    (isBetween 4 4 9) ==> false
    

• pythTriple
  • Takes 3 numbers as inputs (let’s call them a, b and c)
  • Returns:
    • true if the three inputs could be the sides of a right triangle, with the last parameter being the hypotenuse
    • false in all other cases
  • Examples:

    (pythTriple 3 4 5) ==> true
    (pythTriple 6 7 10) ==> false
    (pythTriple 4  3 5) ==> true
    (pythTriple 5 3 4) ==> false
    

• pythTriple2
  • Takes 3 numbers as inputs (let’s call them a, b and c)
  • Returns:
    • true if the three inputs could be the sides of a right triangle, where any of the sides could be the hypotenuse
    • false in all other cases
    • Examples:

      (pythTriple2 3 4 5) ==> #true
      (pythTriple2 6 7 10) ==> #false
      (pythTriple2 4  3 5) ==> #true
      (pythTriple2 5 3 4) ==> #true
      (pythTriple2 4 5 3) ==> #true
      

• exor
  • This is known as the exclusive or operator
  • Takes 2 boolean values as inputs
  • Returns:
    • true if exactly one of the 2 inputs is true
    • false in all other cases
    • Examples:

      (exor #true #true) ==> false
      (exor #true #false) ==> true
      (exor #false #true) ==> true
      (exor #false #false) ==> false
      (exor (> 3 4) (<= 5 6)) ==> true