在haskell中打印出列表中元素的索引

Question

I am new to haskell programming and I am trying to write a program that prints out the index of elements in a list.

Here is the code I have:

Index :: [Int]->[Int]

Index []= []
Index(x:xs)= 0:index (xs+1)

Answer 1

You mean the following?

index :: [a] -> [Int]
index x = [1 .. length x]

[1..4] is shorthand for [1,2,3,4] ...