Was wondering why I get the error: "undefined method `<' for nil:NilClass" when compiling. After looking for reasons why, I found that you cannot use [] on an object with nil as a value. This makes sense, but I don't see why my array would contain nil in it. What am I missing?
def binary_search(n, arr)
middle = arr.length #pick middle value
i = 0
j = arr.length - 1
while i <= j
if arr[middle] == n
return true
elsif arr[middle] < n
i = middle + 1
middle = (i + j) / 2
else
j = middle - 1
middle = (i + j) / 2
end
end
false
end
nums = [76,32,50,90,10,8,15,49]
nums.sort
puts nums.inspect
binary_search(50, nums)
Let's look at a simplified subset of the code:
arr = [76,32,50,90,10,8,15,49]
middle = arr.length # 8
arr[middle] < 50 # NoMethodError
length is 8.arr[8] is nil, because there is no item at index 8. Remember that Ruby indexes begin with 0.nil < 50 is a NoMethodError