They can be 64 bits, but very often on systems today are pointers 32 bits.

也可能为64位，但在通常的,系统中，指针占32位。

哈佛公开课 - 计算机科学课程节选

malloc sizeof So, when I call malloc size of int and int on this system is probably 4 bytes or 32 bits so what am I getting back?

所以，当我调用,在这个系统中int可能是4个字节，或者说32位,那么返回的是什么呢？

哈佛公开课 - 计算机科学课程节选

Now that's changing the more years that pass the more of you have 64-bit computers and the more servers have many, many gigabytes of RAM and so you need actually 64-bits, but for now let's assume a common system whereby a pointer just by definition of the homework is 32 bits.

现在计算机也在改变，也有更多的人,使用64位的计算机，更多的服务器有很多，很多G的内存，那样你就需要64位的，现在我们假设通常的系统中,根据家庭作业所定义的，一个指针为32位。

哈佛公开课 - 计算机科学课程节选