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package src.exercises

import scala.math._
import BigInt.probablePrime
import util.Random

object chap01 {
// 1. In the Scala REPL, type 3. followed by the Tab key. What methods can be
// applied?
// => Do it in REPL. There are many methods including %, &, *, +, toByte, toChar etc.

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// 1. The signum of a number is 1 if the number is positive, -1 if it is negative, and
// 0 if it is zero. Write a function that computes this value.
  
def signum(n: Int) = {
  if (n > 0) 1
  else if (n < 0) -1
  else 0
}                                               //> signum: (n: Int)Int
  
signum(4)                                       //> res0: Int = 1

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// 1. Write a code snippet that sets a to an array of n random integers between 0
// (inclusive) and n (exclusive).
val a = new Array[Int](10)                //> a  : Array[Int] = Array(0, 0, 0, 0, 0, 0, 0, 0, 0, 0)
for(i <- 0 until a.length) a(i) = scala.util.Random.nextInt(10)
a                                         //> res0: Array[Int] = Array(9, 0, 5, 8, 6, 6, 3, 9, 0, 3)

// 2. Write a loop that swaps adjacent elements of an array of integers. For example,
// Array(1, 2, 3, 4, 5) becomes Array(2, 1, 4, 3, 5).
val a = Array[Int](1,2,3,4,5)
a                                         //> res1: Array[Int] = Array(1, 2, 3, 4, 5)

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// 1. Set up a map of prices for a number of gizmos that you covet. Then produce
// a second map with the same keys and the prices at a 10 percent discount.
val gizmos = Map("iPod" -> 20000, "iPhone" -> 45000, "iPad" -> 30000, "iMac" -> 85000)
                                                //> gizmos  : scala.collection.immutable.Map[java.lang.String,Int] = Map(iPod ->
                                                //|  20000, iPhone -> 45000, iPad -> 30000, iMac -> 85000)
val discountedGizmos = for((k, v) <- gizmos) yield (k, v * 0.9)
                                                //> discountedGizmos  : scala.collection.immutable.Map[java.lang.String,Double] 
                                                //| = Map(iPod -> 18000.0, iPhone -> 40500.0, iPad -> 27000.0, iMac -> 76500.0)
  
// 2. Write a program that reads words from a file. Use a mutable map to count

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// 1. Improve the Counter class in Section 5.1, "Simple Classes and Parameterless
// Methods," on page 51 so that it doesn't turn negative at Int.MaxValue.
class Counter {
  private var value = 0
  def increment() { if(value < Int.MaxValue) value += 1 }
  def current = value

  def isLess(other: Counter) = value < other.value // can access private field of other object
}

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//1. Write an object Conversions with methods inchesToCentimeters, gallonsToLiters, and
//milesToKilometers.

object Conversions {
	def inchesToCentimeters(inches: Double) = inches * 2.54
	
	def gallonsToLiters(gallons: Double) = gallons * 3.78541
	
	def milesToKilometers(miles: Double) = miles * 1.60934
}

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//1. Write an example program to demonstrate that
//package com.horstmann.impatient
//is not the same as
//package com
//package horstmann
//package impatient

// File: Demo1.scala
package com {
  package horstmann {

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// Use Gists to store code you would like to remember later on
console.log(window); // log the "window" object to the console

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#!/usr/bin/env scala

import scala.collection.immutable.IndexedSeq

val alphabets = 'A' to 'Z'
val insult = if(args.length > 0) args(0).toUpperCase else "STUPID"
val heading = alphabets filterNot (insult contains(_))

println(getInsult)

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#!/usr/bin/env scala

import scala.collection.immutable.IndexedSeq
import scala.io.StdIn

val version = "Scala Insult Generator v0.1"

val cmdArg = if(args.length > 0) Some(args(0).toUpperCase) else None

val result = cmdArg match {