simple addition program, need help
in [Ruby]
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From: Spencer Spence on 17 Feb 2010 21:56 class Calculater def dothis(x,y) puts x+y end end object = Calculater.new @@number = gets @@number2 = gets object.doThis(number,number2) i'm getting this error, C:\Users\Spencer_2\Documents\NetBeansProjects\RubyApplication1\lib\new_main.rb:12: undefined local variable or method `number' for main:Object (NameError) I'm used to programming in java so I assumed that the doThis(x,y) parameters are just temporary variables in ruby. Am I wrong? -- Posted via http://www.ruby-forum.com/.
From: Alex DeCaria on 17 Feb 2010 22:08 Spencer Spence wrote: > class Calculater > def dothis(x,y) > puts x+y > end > end > > object = Calculater.new > @@number = gets > @@number2 = gets > object.doThis(number,number2) > > i'm getting this error, > C:\Users\Spencer_2\Documents\NetBeansProjects\RubyApplication1\lib\new_main.rb:12: > undefined local variable or method `number' for main:Object (NameError) > > I'm used to programming in java so I assumed that the doThis(x,y) > parameters are just temporary variables in ruby. Am I wrong? The variable number is different than the variable @@number. number is a local variable, whereas @@number is a class variable. So, number (and number2) are undefined when you are calling the doThis method. How about just doing number = gets and number2 = gets, without the @@. -Alex -- Posted via http://www.ruby-forum.com/.
From: Alex DeCaria on 17 Feb 2010 22:12 Alex DeCaria wrote: > Spencer Spence wrote: >> class Calculater >> def dothis(x,y) >> puts x+y >> end >> end >> >> object = Calculater.new >> @@number = gets >> @@number2 = gets >> object.doThis(number,number2) >> >> i'm getting this error, >> C:\Users\Spencer_2\Documents\NetBeansProjects\RubyApplication1\lib\new_main.rb:12: >> undefined local variable or method `number' for main:Object (NameError) >> >> I'm used to programming in java so I assumed that the doThis(x,y) >> parameters are just temporary variables in ruby. Am I wrong? > > The variable number is different than the variable @@number. number is > a local variable, whereas @@number is a class variable. So, number (and > number2) are undefined when you are calling the doThis method. > > How about just doing number = gets and number2 = gets, without the @@. > > -Alex An additional thing to keep in mind. gets returns the input as a string. To make them numbers you should do number = gets.to_i (for integers) or gets.to_f (for floats). --Alex -- Posted via http://www.ruby-forum.com/.
From: Spencer Spence on 17 Feb 2010 22:17 ah thank you, not totally sure why I made number a class variable. So that's figured out but when i run it, if i type 2 and 2, it prints 2 2 instead of adding them like integers it adds them like strings. -- Posted via http://www.ruby-forum.com/.
From: Glenn on 17 Feb 2010 23:02
[Note: parts of this message were removed to make it a legal post.] Spencer, @@number and @@number2 are class variables. number and number2 are local variables. Also, Ruby is case sensitive, so the doThis method and the dothis method are actually 2 different methods. ________________________________ From: Spencer Spence <spencaatee(a)live.com> To: ruby-talk ML <ruby-talk(a)ruby-lang.org> Sent: Wed, February 17, 2010 9:56:14 PM Subject: simple addition program, need help class Calculater def dothis(x,y) puts x+y end end object = Calculater.new @@number = gets @@number2 = gets object.doThis(number,number2) i'm getting this error, C:\Users\Spencer_2\Documents\NetBeansProjects\RubyApplication1\lib\new_main.rb:12: undefined local variable or method `number' for main:Object (NameError) I'm used to programming in java so I assumed that the doThis(x,y) parameters are just temporary variables in ruby. Am I wrong? -- Posted via http://www.ruby-forum.com/. |