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We're kind of restricting ourselves to only certain chunks of memory, at least for now, but it certainly creating problems.
我们现在我们自己只能在某一块内存中,至少是现在，当然这样也会产生问题。
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RAM is this memory recall or, as you'll soon find in problems Set One, that's used for ephemeral purposes.
内存是随机存储器，你们将,在习题集1中发现，它们用来短暂存储的目的。
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Here's the problem with that technique, and by the way, a number of programming languages use this, including Lisp.
这会指向元素的值，然后对内存进行切分,关于这种技术有个问题，顺路说下。
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So, you know, we've got a bunch of juicy topics to dive into this week involving pointers and memory.
这周我们有很多有趣的主题,包括指针和内存。
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One of the perhaps easiest ones to put your finger on is what if the computer is out of memory?
一个可能的情况是,计算机的内存不足？
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Alright, so it turns out there're two other useful types that you don't get for free out of the box.
我们还是回到这里，还有两种很有用的数据类型,这两种都不用担心内存不足。
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There are absolutely going to be times where you're running a program where the programmer, say you, didn't possibly know in advanced how much RAM the program was going to need.
它们总是在,程序员运行程序的地方，你可能预先不知道那个程序,需要多少内存。
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I've been using the blackboard a little ad hoc here, but suppose I neaten things up here now and present this rectangle is let's say R RAM, the memory inside of your computer.
我在这里特别地使用这块黑板，假如我整理这些东西，把它们呈现,这个长方形，假如说就是内存，你电脑的内存。
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Why not write the program in a way where you figure out dynamically when the program is run how much memory you need rather than hard coding in two with or within that constant.
为什么不写一个可以动态的方式写那个程序,程序可以动态分配内存,而不是用常量硬编码两个值。
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And by that, I mean, not how much memory do I need to store the size of the input, it's really how much internal memory do I use up as I go through the computation?
需要占用多少内存,我意思并不是，存储输入需要多少内存,而是当我完成这个？
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So both of these stories involve floating point values, but only in this case am I actually allocating memory.
所以这两个故事都涉及到浮点类型，但是只有那样我们才能真正地分配到内存。
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When you call a function, what actually happens is that function gets its own chunk of memory that's identical in size to the data type that it expects.
当你调用一个函数，实际上发生的是,函数得到了自己的内存块，相同的类型,是占有一样大小的内存的。
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But we know already from week zero that computers ultimately represent all information with numbers, and if they want to represent letters inside memory, well what do they do or what do they use?
但是自从上周我们已经知道,计算机最终是用数字来表示所有的,信息，如果它们要描绘,在内存中的字母，它们该怎么做，用什么方式呢？
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And one of the ways you can make a program crash, intentionally or not, is to essentially use up too much memory or call too many functions and what happens is, bam, one hits the other and bad things happen.
其中一个方式能使你的程序崩溃掉，有意或无意的,它本质上使用了太多的内存,或者调用了太多的函数，所发生的，崩掉，一个冲突了另一个，然后发生了坏事情。
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I have no idea what's here at the moment so I'm just going to draw a question mark because that memory might have been used previously for some other purpose, but we know it's currently available to us so we have four bytes of memory.
我不知道在此刻这里是什么,所以我画一个问号，因为那块内存可能在之前,为其它的目的而使用过，但是我们知道它可以为我们所使用,这样我们就有4个字节的内存。
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Well, again, just as I said verbally a moment ago, if you're going here, you're literally touching, trying to read or change memory that's beyond the boundaries of a chunk of memory that you're supposed to be touching based on its length.
嗯，再次强调，就像我刚才说的，如果你从这里出发，你将依次接触到，试着读取或者改变内存,如果超出了你可以使用的,内存块长度的界限。
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Its name is malloc for memory allocation and what malloc does for us is we say, hmm, the user has typed in a three-letter word.
它为我们分配内存地址,它为用户输入的3个字母单词,分配地址。
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You actually need to kind of do this and then you can swap these two numbers but it requires 50 percent more memory.
你实际上需要这样做,然后才能交换两个数字,但是它需要多50%的内存。
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Two pieces of memory actually touching each other or you touching memory that you don't actually own, in which case the computer doesn't really know what to do and just, bam.
两块内存相互覆盖,或者你覆盖了不存在的内存，那样的话计算机不知道,该怎么做，只有崩溃。
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Which may take up some arbitrary amount of memory. In that case, I'm back to this problem.
然后将接下来的每一个内存块设置为,指向数组对应元素值的指针。
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Well, if that function calls another function, you put another tray on, and so that new tray represents that function's chunk of memory.
好的，如果那个函数调用另一个函数，你再放一个托盘在上面，新的托盘代表,那个函数的内存块。
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You can touch almost any part of memory in the computer systems that you want with your program, but do you want to?
通过你的程序，你可以触及到计算机系统,内存的任意部分，但是那是你想要的吗？
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Or another way of thinking about it, is remember I said when I call that class definition it creates an instance, that's a pointer to some spot in memory that's got some local information around it.
也就是一个指向，内存中某处的指针,这个地方存有一些,这个实例的信息，浅意义的相等也就是说,看看这两个东西是不是。
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Or another way of saying it is, we're going to use as the basic steps, those operations that run in constant time, so arithmetic operations.
我们用可以在恒定时间内完成的操作,算法，比较,内存读取。
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It's just some random chunk of four bytes that happens to be available at this point in time, but I can put something there.
只是一些随机的四字节的内存块,在这里是可以使用的，但是我可以在那里放置东西。
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So the heap is a chunk of memory in a computer's RAM that's conceptually allocated to what's called dynamic memory allocation.
堆是在计算机RAM中的一块内存,它可以进行,动态内存分配。
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Right now it's empty, actually it's not quite empty, it has a pointer back to the class.
当我调用了这个类的，定义声明的时候，它在内存中的特定点。
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When we talk about space, what we usually refer to is, how much computer memory does it take to complete a computation of a particular size?
我们经常指的是，当我们计算，一个特定大小的问题的时候,要占用计算机的多少内存？
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I mean, you grew up in an age when computers were blazingly fast, and have tons of memory, so why in the world do you care about efficiency?
我的意思是你们是伴随着,计算机快速发展成长的，计算机都有这么大的内存,那还在乎效率干嘛呢？
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