Number one, the basic structure is that you have a pointer and it points over to a pointee, but the pointer and pointee are separate and the common error is to set up a pointer but to forget to give it a pointee.

第一，基本结构是，你有一个,指向数据的指针，但是那个指针和数据,是分开的，通常错误是声明了一个指针,但是没有指向一个数据。

哈佛公开课 - 计算机科学课程节选

y >> Yeah. We allocated the pointer y but we never set it to point to a pointee.

>，是的，我们分配了指针y，但是,没有指向任何数据。

哈佛公开课 - 计算机科学课程节选