/**
 * 2. In the Scala REPL, compute the square root of 3, and then square that value. By how much does the result differ from 3? (Hint: The res variables are your friend.)
 */
scala> math.sqrt(3)
res1: Double = 1.7320508075688772

scala> res1*res1
res2: Double = 2.9999999999999996

scala> 3 - res2
res3: Double = 4.440892098500626E-16

// 3. Are the res variables val or var?
scala> res1 = 3
<console>:11: error: reassignment to val
       res1 = 3
            ^

/**
 * 4. Scala lets you multiply a string with a number—try out "crazy" * 3 in the REPL. 
 * What does this operation do? Where can you find it in Scaladoc?
 */
// StringOps.* : Return the current string concatenated n times.
scala> "crazy "*3
res6: String = "crazy crazy crazy "

/**
 * 5. What does 10 max 2 mean? In which class is the max method defined?
 */
 // Int.max: Returns this if this > that or that otherwise.
scala> 10 max 2
res7: Int = 10

scala> 10.max(2)
res8: Int = 10

/**
 * 6. Using BigInt, compute 21024.
 */
scala> BigInt(2) pow 1024
res13: scala.math.BigInt = 179769313486231590772930519078902473361797697894230657273430081157732675805500963132708477322407536021120113879871393357658789768814416622492847430639474124377767893424865485276302219601246094119453082952085005768838150682342462881473913110540827237163350510684586298239947245938479716304835356329624224137216

/**
 * 7. What do you need to import so that you can get a random prime as probablePrime(100, Random), 
 * without any qualifiers before probablePrime and Random?
 */
scala> import scala.util.Random
import scala.util.Random

scala> import scala.math.BigInt
import scala.math.BigInt

scala> import scala.math.BigInt.probablePrime
import scala.math.BigInt.probablePrime

scala> probablePrime(100, Random)
res14: scala.math.BigInt = 931669304734992063893063804797

/**
 * 8. One way to create random file or directory names is to produce a random BigInt 
 * and convert it to base 36, yielding a string such as "qsnvbevtomcj38o06kul". 
 * Poke around Scaladoc to find a way of doing this in Scala.
 */
scala> probablePrime(100, Random) toString 36
res15: String = 2mojnrl2508jtnu26t01

/**
 * 9. How do you get the first character of a string in Scala? The last character?
 */
scala> "Hello".head
res20: Char = H

scala> "Hello".last
res21: Char = o

/**
 * 10. What do the take, drop, takeRight, and dropRight string functions do? 
 * What advantage or disadvantage do they have over using substring?
 */
 // StringOps.drop: Selects all elements except first n ones.
 // StringOps.dropRight: Selects all elements except last n ones.
 // StringOps.take: Selects first n elements.
 // StringOps.takeRight: Selects last n elements.
scala> "Hello World!" take 6
res22: String = "Hello "

scala> "Hello World!" drop 6
res23: String = World!

scala> "Hello World!" takeRight 6
res24: String = World!

scala> "Hello World!" dropRight 6
res25: String = "Hello "