Question on while loop to script

Ruby
1

Hi guys,

I’m new to ruby and I’m writing simple programs to help my understanding
of ruby. I wrote the program below and I would like to know if you guys
could recommend a while loop to use before the if statement so the
program doesn’t end until a key is pressed? I want it to keep running
until the user quits. Also does anyone think I can make the program
better?class OhmsLaw
def initialize(voltage, current, resistance)
@voltage = voltage
@current = current
@resistance = resistance
end
def voltageNil
@current * resistance
end
def currentNil
@voltage / @resistance
end
def resistanceNil
@voltage / @current
end
def to_s
“String representation of OhmsLaw V: #{@voltage}, I: #{@current}, R:
#{@resistance}”
end

#This will make these variables accessoable from outside
#of the class

attr_accessor :voltage, :current, :resistance
#solve4Current can be used for :currentNil as an alias for it
alias :solve4Current :currentNil
end

#created a new object called solve that will take V,I,R as inputs
solve = OhmsLaw.new(9.0, nil, 2)
#attr_accessor allows us to change voltage of 9 to 16 volts from
#outside of the class
solve.voltage = 16

if solve.voltage == nil
puts solve.voltageNil
elsif solve.current == nil
puts solve.solve4Current
else
puts solve.resistanceNil
end

puts “#{solve}”

2

On Jul 22, 2013, at 6:50 PM, “Talal B.” [email protected] wrote:

@current = current
end
end
puts solve.solve4Current
else
puts solve.resistanceNil
end

puts “#{solve}”

–
Posted via http://www.ruby-forum.com/.

Welcome!

I’m of two minds here:

  1. writing a REPL (read-eval-print loop) is a worthy exercise in itself,
    so yes
  2. if you just want to work with your class, you can use irb as your
    REPL, so maybe not yet
3

You can make your code a bit shorter still.

puts “#{solve}”

No need to do that. Simply do:

puts solve

And also:

if solve.voltage == nil
puts solve.voltageNil
elsif solve.current == nil
puts solve.solve4Current
else
puts solve.resistanceNil
end

could become:

if solve.voltage.nil?
puts solve.voltageNil
elsif solve.current.nil?
puts solve.solve4Current
else
puts solve.resistanceNil
end

4

Thanks so much for your help but what I’m looking for is

while key.pressed =! q
if solve.voltage.nil?
puts solve.voltageNil
elsif solve.current.nil?
puts solve.solve4Current
else
puts solve.resistanceNil
end
end

Does anyone know how i may be able to accomplish this goal?

5

On Jul 23, 2013, at 3:55 PM, Talal B. [email protected] wrote:

Thanks so much for your help but what I’m looking for is

while key.pressed =! q

loop do
print "Type ‘q’ to quit: ’
break if gets[0] == ‘q’