Exercise 3.55 · 习题

Exercise 3.55: Define a procedure
partial-sums that takes as argument a stream S and returns the
stream whose elements are S
0, S
0

+

S
1, S
0

+

S
1

+

S
2

,

….

For example, (partial-sums integers) should be the

stream 1, 3, 6, 10, 15, ….

练习 3.55：定义一个过程 partial-sums，它以流 S 为参数，返回一个流，其各元素为 S₀，S₀ + S₁，S₀ + S₁ + S₂，……。例如，(partial-sums integers) 应得到流 1, 3, 6, 10, 15, ……。