）

问题在于，从加法器函数返回的lambdas包含对不再存在的 x 变量的悬挂引用。捕获副本（ [=] 或 [i] ）而不是引用（ &] ），一切都应该工作。

The One problem in that code is that the lambdas returned from the adder function contain dangling references to the x variable that no longer exists. Capture by copy ([=] or [i]) instead of a reference ([&]) and everything should work.