Consider this code:
def get_int_values
[gets, gets].map{ |s| s.chomp.to_i }
end
puts "Would you like to [add], [multiply], or [subtract]?"
response = gets.chomp
case response.downcase
when 'add'
puts "Which numbers would you like to add?"
operator = :+
when 'subtract'
puts "Which numbers would you like to subtract?"
operator = :-
when 'multiply'
puts "Which numbers would you like to multiply?"
operator = :*
end
answer = get_int_values.inject(operator)
puts "The answer is... #{ answer }"
The idea is to follow the "DRY" principle: "DRY" means "Don't Repeat Yourself", which the vast majority of the time, is a really good thing.
To help avoid typing mistakes I'd recommend doing something like:
puts "Would you like to [a]dd, [m]ultiply, or [s]ubtract?"
response = gets.chomp
case response[0].downcase
then change the when clauses to match the first letter of the desired operation.
Which will work unless response is empty. You can figure out how to handle that.
another way to obtain answer, once operator is determined, is answer = gets.to_i.send(operator, gets.to_i)
That's true, but here's why I refactored the code the way I did: If, for some reason, there was a need to operate on more than two values, only one thing has to be changed:
[gets, gets].map{ |s| s.chomp.to_i }
could become:
[gets, gets, gets].map{ |s| s.chomp.to_i }
Or, better, could be transformed to something like:
def get_int_values(n)
n.times.map { gets.chomp.to_i }
end
Nothing else will have to change except to find out how many values are needed.
Now, to do it all right would require different text to alert the user that multiple values are expected, but that's easily done by letting letting the user say how many they want to enter, and then prompting for each gets:
def get_int_values(n)
n.times.map.with_index { |n|
print "Enter value ##{ 1 + n }: "
gets.chomp.to_i
}
end
puts "Would you like to [add], [multiply], or [subtract]?"
response = gets.chomp
puts "How many values?"
num_of_values = gets.to_i
case response.downcase
when 'add'
puts "Which numbers would you like to add?"
operator = :+
when 'subtract'
puts "Which numbers would you like to subtract?"
operator = :-
when 'multiply'
puts "Which numbers would you like to multiply?"
operator = :*
end
answer = get_int_values(num_of_values).inject(operator)
puts "The answer is... #{ answer }"
inject can scale up easily because it doesn't presuppose knowledge about the number of values being operated on.
I think with_index in n.times.map.with_index is an artifact you forgot to delete.
It was deliberate but I like this better:
def get_int_values(n)
1.upto(n).map { |n|
print "Enter value ##{ n }: "
gets.chomp.to_i
}
end
