Databases
StackOverflow2013
Postsdbo
POError while trying to initialise a class in scala
 

Note that there are some explanatory texts on larger screens.

plurals
  1. POError while trying to initialise a class in scala
    primarykey
    data
    text
    <p>I am trying to make a class for the purpose of adding rational numbers</p> <pre><code>class Rational(val numerator: Int, val denominator: Int) { require(denominator != 0) def this(numerator: Int) = this(numerator, 1) def +(addend: Rational): Rational = { new EquivalentRationals(this, addend).sum } def +(addend: Int): Rational = new Rational(numerator + (denominator*addend), denominator) override def toString = numerator + "/" + denominator } class EquivalentRationals(a: Rational, b: Rational) { val first: Rational = new Rational(a.numerator * b.denominator, a.denominator * b.denominator) val second: Rational = new Rational(b.numerator * a.denominator, b.denominator * a.denominator) def sum(): Rational = new Rational(first.numerator + second.numerator, second.denominator) def difference(): Rational = new Rational(first.numerator - second.numerator, second.denominator) override def toString = first + " " + second } </code></pre> <p>I get the following error when i try to create an object out of the first class</p> <blockquote> <p>:23: error: type mismatch; found : Rational(in object $iw)(in object $iw)(in object $iw)(in object $iw) required: Rational(in object $iw)(in object $iw)(in object $iw)(in object $iw) new EquivalentRationals(this,addend).sum()</p> </blockquote> <p>I would like to know why this occurs and i would also be grateful for any suggestions of alternative approaches to adding rational numbers which also use a separate class for representing equivalent fractions. (there is a rational class which already accomplishes this without using a separate class in the book "programming in scala") edit: The problem only seems to occur when using scala-mode in emacs. I tried to run it by selecting the option "load file in interpreter", so although it runs via the command line i am still curious as to why it doesn't in "inferior-scala"</p>
    singulars
    1. This table or related slice is empty.
    1. This table or related slice is empty.
    1. PTQuestion
    1. USVinicius Miana
    1. USHerr Char
    plurals
    1. This table or related slice is empty.
    1. This table or related slice is empty.
    1. This table or related slice is empty.
    1. This table or related slice is empty.
    1. VO
      singulars
      1. POError while trying to initialise a class in scala
      1. This table or related slice is empty.
      1. VTApproveEditSuggestion
    1. COtry changing new EquivalentRationals(this,addend).sum() to (new EquivalentRationals(this,addend)).sum()
      singulars
      1. POError while trying to initialise a class in scala
      1. USSimon Todd
    2. COWhat is your scala version? Works for me in `scala 2.10.1`.
      singulars
      1. POError while trying to initialise a class in scala
      1. USsenia
    3. CO@SimonTodd: `new EquivalentRationals(this,addend).sum()` works fine.
      singulars
      1. POError while trying to initialise a class in scala
      1. USsenia
 

Querying!

 
Guidance
A row detail

Detail views are divided into sections. All the information in the data section comes from columns in the selected row. The other sections display data from other, related rows.

Related data can be related in a to-one or a to-many fashion. Captions of data related in a to-many fashion link to a list view showing a filtered view of the table.

Try moving around until you find a non-empty to-many entry and click on the label to get to one. You can move back to the root by clicking on the database name in the header.

SQuiL has stopped working due to an internal error.

If you are curious you may find further information in the browser console, which is accessible through the devtools (F12).

Reload