Update scala-quiz.md (Ebazhanov#308)

ответы по скале и новые вопросы

scala/scala-quiz.md

@@ -6,7 +6,7 @@ Scala Assessment
 - [ ] One is a Java object, the other is a Scala object.
 - [ ] clone() will copy class structures but not the data, while copy() will also copy data into new objects.
 - [ ] There is no difference.
-- [ ] copy() allows you to change values during the copying process; clone() does not.
+- [x] copy() allows you to change values during the copying process; clone() does not.
 
 
 #### Q2. What value does this code return? 
@@ -19,22 +19,22 @@ m1("a")
 - [ ] a
 - [ ] 2
 - [ ] b
-- [ ] 1
+- [x] 1
 
 
 #### Q3. What is one way to avoid low-level parallelization details?
 
 - [ ] monads
 - [ ] literal functions
 - [ ] partially applied functions
-- [ ] parallel collections
+- [x] parallel collections
 
 
 #### Q4. What do you use in ScalaTest to see a detailed diagram of error messages when a test fails?
 
 - [ ] ArgumentExceptions
 - [ ] AssertionException
-- [ ] DiagrammedAssertions
+- [x] DiagrammedAssertions
 - [ ] JUnit
 
 
@@ -43,7 +43,7 @@ m1("a")
 - [ ] Array
 - [ ] ImmutableCollection
 - [ ] List
-- [ ] Tuple
+- [x] Tuple
 
 
 #### Q6. After defining a function in the interpreter, Scala returns the following. What does the 
@@ -54,15 +54,15 @@ myfnc: ()Unit
 
 - [ ] The function has no side effects.
 - [ ] The function takes no parameters. 
-- [ ] The function returns no value.
+- [x] The function returns no value.
 - [ ] Returning unit types to the function is a closures.
 
 
 #### Q7. What type of number is 1234.e5?
 
 - [ ] hexadecimal
 - [ ] short
-- [ ] floating point
+- [x] floating point
 - [ ] long
 
 
@@ -71,7 +71,7 @@ myfnc: ()Unit
 - [ ] List[(String, String)]
 - [ ] List[(Array, Array)]
 - [ ] List[(Array, Array)]
-- [ ] List
+- [x] List
 
 
 #### Q9. What type of object does this code create? 
@@ -82,7 +82,7 @@ val x = (1234, "Active")
 
 - [ ] List
 - [ ] Map 
-- [ ] Tuple
+- [x] Tuple
 - [ ] Array 
 
 
@@ -91,22 +91,22 @@ val x = (1234, "Active")
 - [ ] AnyVal
 - [ ] AnyRef 
 - [ ] Method
-- [ ] Null
+- [x] Null     NOT SURE
 
 
 #### Q11. For the for-yield construct, is the scope separate between for-body and yield-body?
 
-- [ ] Yes and no. It is different depending on the for construct and what it does.
+- [x] Yes and no. It is different depending on the for construct and what it does.                  NOT SURE
 - [ ] Yes, because the for section does not expose its scope.
-- [ ] No, because for-yield shares the same scope, even though they are within separate curly braces.
+- [ ] No, because for-yield shares the same scope, even though they are within separate curly braces.    
 - [ ] Yes, because they are within different curly braces.
 
 
 #### Q12. What is one way to implement pattern matching on methods?
 
 - [ ] using regex
 - [ ] using monads
-- [ ] using string matching
+- [x] using string matching
 - [ ] using case classes
 
 
@@ -118,14 +118,14 @@ val z = y::List('c')
 ```
 
 - [ ] List(a,b,c)
-- [ ] List(List(a, b), c)
+- [x] List(List(a, b), c)
 - [ ] List(c,a,b)
 - [ ] List(c,List(a,b))
 
 
 #### Q14. What term is used to specify a precondition?
 
-- [ ] assert
+- [x] assert
 - [ ] require
 - [ ] precondition
 - [ ] mustHave
@@ -134,6 +134,7 @@ val z = y::List('c')
 #### Q15. Which Scala type may throw an exception or a successfully computed value, and is commonly used to trap and propagate errors?
 
 ##### answers missing
+Answer should be Option: Some or None
 
 
 #### Q16. What is the data type of y after this code is executed?  
@@ -142,7 +143,7 @@ val z = y::List('c')
 val y = (math floor 3.1415 * 2)
 ```
 - [ ] short
-- [ ] double
+- [x] double
 - [ ] int
 - [ ] bigInt
 
@@ -151,14 +152,14 @@ val y = (math floor 3.1415 * 2)
 - [ ] %
 - [ ] _
 - [ ] ^
-- [ ] *
+- [x] *
 
 
 #### Q18. You have created an array using val. Can you change the value of any element of the array—and why or why not?
 
 - [ ] Yes, the reference to the array is immutable, so the location that the array points to is immutable. The values in the array are mutable.
 - [ ] The 0th element is immutable and cannot be modified. All other elements can be modified.
-- [ ] Yes, val does not make arrays immutable.
+- [x] Yes, val does not make arrays immutable.
 - [ ] No, val makes the array and values of the array immutable.
 
 
@@ -171,18 +172,54 @@ def main () {
 ```
 - [ ] 1,2,3,4,5
 - [ ] 0,1,2,3,4
-- [ ] 1,2,3,4
+- [x] 1,2,3,4
 - [ ] 2,3,4,5
 
 
 #### Q20. What do you call objects with immutable state?
 
-- [ ] singletons
+- [x] singletons
 - [ ] stationary objects
 - [ ] functional objects
 - [ ] fixed objects
 
 
+#### Q21. You have written a Scala script. How would you access command-line arguments in the script?
+
+- [x] use array named args
+- [ ] use tuple named args
+- [ ] use numbered variables with a _ prefix for example _ 1, _ 2, _ 3
+- [ ] use numbered variables with a $ prefix - for example $1, $2, $3
+
+
+#### Q22. What does this code return? val x = 3; if (x >2) x = 4 else x = x*2
+
+- [ ] 4
+- [x] an error
+- [ ] 6
+- [ ] 3
+
+
+#### Q23. Which statement returns a success or a failure indicator when you execute this code?
+val MyFuture = Future {runBackgroundFunction() }
+
+- [x] myFuture.onComplete
+- [ ] myFuture(status)
+- [ ] myFuture.Finished
+- [ ] complete(myFuture)
+
+
+#### Q24. To denote a parameter that may be repeated, what should you place after type?
+
+- [ ] %
+- [ ] &
+- [ ] _
+- [x] *
 
 
+#### Q25. What is called when a superclass has more than one subclass in Scala?
 
+- [ ] polyinheritance
+- [ ] multilevel inheritance
+- [ ] multimode inheritance
+- [x] hierarchical inheritance