Scala : add constructor, method less and max to Rationals

1 files changed, 12 insertions, 0 deletions

diff --git a/Scala/sandbox/3-rationals.scala b/Scala/sandbox/3-rationals.scala
index 3eec82c..868f216 100644
--- a/Scala/sandbox/3-rationals.scala
+++ b/Scala/sandbox/3-rationals.scala
@@ -1,7 +1,14 @@
 
 object Rationals {
 
+  // primary constuctor
   class Rational(x :Int, y: Int) {
+    require(y != 0, "denominator must be non zero") // throws IllegalArgumentException
+    assert(y != 0)                                  // throws AssertionError
+
+    // another constructor
+    def this(x: Int) = this(x, 1)
+
     private def gcd(a: Int, b: Int): Int = if (b == 0) a else gcd(b, a % b)
     private val g = gcd(x, y)
     def numer = x / g
@@ -9,6 +16,10 @@ object Rationals {
 
     def neg = new Rational(-numer, denom)
 
+    def less(that: Rational) = this.numer * that.denom < that.numer * this.denom
+
+    def max(that: Rational) = if (this.less(that)) that else this
+
     def add(that: Rational) =
       new Rational(
         numer * that.denom + that.numer * denom,
@@ -24,6 +35,7 @@ object Rationals {
     println("Rationals")
     println(new Rational(2, 3).add(new Rational(3, 4)).toString)
     println(new Rational(1, 3).sub(new Rational(5 ,7)).sub(new Rational(3, 2)).toString)
+    println(new Rational(1, 3).max(new Rational(5 ,7)).toString)
   }
 
 }