scala-Sixth Chapter-rational

The knowledge points involved:
Check for prerequisites.

function overloading.

Operator overloading.

Console input.

Private functions.

An implicit conversion.

<pre name= "code" class= "java" >import java.io.bufferedreader;import Java.io.file;import Java.io.fileinputstream;import Java.io.ioexception;import Java.io.inputstreamreader;import Java.io.PrintStream; Import Java.io.printwriter;import Java.math.bigdecimal;class Rational (N:int, D:int) {require (d! = 0);//Check Prerequisites private  Val g = gcd (N.abs, d.abs);  Val num:int = n/g;    Val den:int = d/g;    Override Def toString = n + "/" + d;//overload tosting def this (n:int) = This (n, 1); def + (that:rational): rational =//define operation symbol new Rational (num * that.den + that.num * den, den * that.den) de F * (that:rational): rational = new rational (num * that.num, den * that.den) def * (i:int): rational =//reload * New Ra tional (I*num, den) def lessthan (that:rational) = This.num * That.den < That.num * This.den def max (that:ratio NAL) = if (This.lessthan (that)) so else this private def gcd (N:int, d:int): Int =//Private Function if (d==0) n Else gcd (d, n% d)}object Rational {def maiN (args:array[string]) {var bf = new BufferedReader (new InputStreamReader (system.in));    var line = Bf.readline ();    var eles = Line.split ("") val R1 = new Rational (integer.parseint (eles (0)), Integer.parseint (Eles (1)));    line = Bf.readline ();    Eles = Line.split ("");    Val R2 = new Rational (integer.parseint (eles (0)), Integer.parseint (Eles (1)));    Val R3 = R1 + R2;    Val R4 = new Rational (2);    Implicit def inttorational (x:int) = new Rational (x)//implicit conversion//implicit conversion to be placed in scope, not within class!    Val R5 = 2 * R3;  println (R5); }}

scala-Sixth Chapter-rational