How to iterate over items in a list using previous item [duplicate]

Question

list = [1, 2, 3, 4, 5] How can I iterate over each item using the previous item? The previous item for the first element would just be 0. For example, something like this:

print(list[1] + 0)
print(lst[2] + list[1])
print(lst[3] + list[2])

I know you can do this with sum(), but I need to specifically iterate like this because the actual code is much more complicated than that.