i tred creating a method called "Sum_plus_one" that accepts an array argument containing integers. Themethod should return the sum of the integers in the array after adding one to each of them.
example: sum_plus_one([1,2,3])
result should be: 9
my code looks like this
def sum_plus_one(*nums)
for num in nums
num + 1
end
total = 0
for num in nums
total += num
end
return total
end
Why not do a little bit of math beforehand and see that summing the array-elements-plus-one is the same as summing the elements and then adding the array length? For example:
(5+1) + (6+1) + (11+1) = 5 + 6 + 11 + (1 + 1 + 1)
= 5 + 6 + 11 + 3
That gives you something nice and simple:
array.inject(:+) + array.length
map/reduce is handy here:
def sum_plus_one(nums)
nums.map(&:succ).reduce(:+)
end
Edit:
here is one way to make your code work:
def sum_plus_one(nums)
nums.map! do |num|
num + 1
end
total = 0
for num in nums
total += num
end
return total
end
do |num| num + 1 end). In this case it adds 1 to each element in the array. We tend to use iterators in Ruby. It relieves us from keeping track of i's and j's and makes for clean, succinct, flexible code. See the map/reduce example above for comparison.Functional Style Version
[1, 2, 3].reduce(0) {|acc, n| acc + n + 1}
[105] pry(main)> arr
=> [1, 2, 3]
[106] pry(main)> arr.inject(0) { |var, i| var + i + 1 }
=> 9
So the method would look like
def sum_plus_one(*nums)
nums.inject(0) { |var, num| var + num + 1 }
end
var + num + 1 without assigning it to var.your problem is that you need to assign your num + 1 value to the corresponding element of the array that you are enumerating in the first loop.
maybe something like this:
for i in (0...nums.count)
nums[i] += 1
end
after that your program should work
(yes, you can use fancy libraries or constructs instead of the above loop)
please note that you can eliminate the top loop and just add num + 1 to your total in the second loop.
num + 1has no effect on the contents of the array.