I've problem returning value from recursive function.
def ask_question(question)
print question
answer = STDIN.gets.chomp
ask_question question if answer.empty?
return answer
end
The first time the answer is returned properly but I got empty string in next calls. Why is that?
That is because you aren't returning the value returned by your recursive calls to ask_question.
def ask_question(question)
print question
answer = STDIN.gets.chomp
answer = ask_question question if answer.empty?
return answer;
end
All you were doing is returning the first user input value (in your case an empty string) when the method was done.
Your code does not work because the variable answer you return it's always the one in the first iteration (each call has its own local scope). So a possible solution is:
def ask_question(question)
print question
answer = STDIN.gets.chomp
answer.empty? ? ask_question(question) : answer
end
Note though that this recursive construction is fine with languages that support tail-call optimization, but Ruby does not force it, so it will usually create a new stack frame for each iteration and eventually it will blow. I'd recommend looping, for example:
def ask_question(question)
loop do
print question
answer = STDIN.gets.chomp
break answer unless answer.empty?
end
end
ctrl+c (for *nix), you'll see a stack trace proportionate to the number of times you hit enter.