"Fertilizers represent about 20 percent of the input costs in rice production for farmers."
VOA: standard.2010.07.28
So we'll talk a bit more about this idea of functions today, but, get int, again, can think of it as a black box, whose purpose in life is to prompt the human for input and pester the human if he or she doesn't actually give it int, but then once it has that, has entered it from the user, it's quote unquote, returns it to you.
所以我们进今天将多讨论点这个函数的概念,但是,GetInt,我们可以把它当做一个黑盒子,它的唯一目的是提示人们来输入,并且如果他或她没有,给它int数,则会纠缠用户,但是一旦它得到了,用户输入的int数,对输入进行引用,返回给你。
These things run for variable amounts of time because they take input, a list of size of some amount.
而这一段的执行时间是可变的,因为它们需要输入一个包含一些元素的列表。
Another way of saying it is, if I, for example, 10 increase the size of the input by 10 10 the amount of time increases by 10.
另一种说法就是,例如,我把输入的规模增加0,解决花费的时间也会增加。
It was a complete waste of time, unless the goal in life was simply to pester the user for some input.
刚才的时间就完全浪费了,除非那个唯一的目的,是简单地纠缠用户索要一些输入。
Need to get the base in. Second thing I want to do, I need to get the height, so I'm going to input a value for the height, also as a float, a floating point.
也就是输入底的值,第二件我想要做的,事情就是得到三角形的高,因此我会输入一个值作为三角形的高,同样也是一个浮点数。
ReadFloat We'll look at it in a second. Let me sort of set the stage up for this -- suppose I want to input -- I'm sorry I want you as a user to input a floating point number.
名字叫,我们来看一会,我先来设置下情景-,假设我想输入,抱歉,我希望你们作为用户来输入一个浮点数。
Because if I don't specify a name for this input, I have no way of actually referring to it in subsequent lines of code.
因为如果我不给这个输入定义一个名字,在随后的代码中,我就没有办法使用它。
You have to jump through hoops just to ask the user for a piece of input which should be really the thing a language prioritizes.
你要百依百顺才能从用户那里得到一个输入,这个输入可能只是一个,语言优先级。
One is, what's the thing I print out when I ask for the input?
第一件是当我要求输出的时候,我输出的内容?
So if I were to solve this problem, here's the way I would do it. I would say, first thing I want to do, is I want to input a value for the base as a float.
如果我想要解决这个问题,这就是我要解决它的方式了,第一件我要做的事情就是要,输入一个浮点数作为三角形的底。
The format is the same. I'm going to ask for some input, and then I am going to use that procedure to check, is this the right type of value. And I'm trying to use that to do the coercion if you like. Same thing if it works, I'm going to skip that, if it not, it's going to throw the exception.
格式是一样的,我需要一些输入,然后我要用一个过程来检查,是否是正确的值,然后你就可以做强制转换了,如果能运行,那是一样的,我打算跳过这段,如果不正确,那就会抛出一个异常。
It is certainly possible, for example, that a quadratic algorithm could run faster than a linear algorithm. It depends on what the input is, it depends on, you know, what the particular cases are. So it is not the case that, on every input, a linear algorithm is always going to be better than a quadratic algorithm.
一个二次平方级复杂度的算法,当然也是可能跑的比线性复杂度算法快的,这取决于,你知道的,输入以及特定的案例,因此并不是对于每个输入,线性复杂度就一定会,比二次平方级复杂度的算法的表现要好,只是通常来说是这样的。
So you have to somehow convert the source code, the C code into 0s and 1s and for that process there exist this tool called a compiler that someone else wrote that takes this stuff as input and produces this stuff as output.
所以你必须把源代码,即C语言代码转换成二进制文件,这个过程就需要我们提到的编译器了,它是由别人编写的一个软件,以这些代码作为输入,将会产生的输出。
It ran through that sequence of instructions, in particular it bound x to the value three, x and then it took x times x, got the value of x multipied by x, which of course is nine, bound that to the value of x, and then it printed out the value, and now it's sitting here waiting for an input.
程序按照指令的顺序去执行的,首先是把x和3这个值进行了绑定,然后把x乘以,得到了x乘以x的值,当然也就是9了,然后把x和这个值进行了绑定,然后显示出这个值,然后就等待输入。
I'm going to use the CS50 Library instead for user input I'm saying say something then I'd get a string from the user and I call time s1 and then I say, say something, s2 and then I get another string from the user and call it s2 and apparently this program's purpose in life is to tell me yes or no the user said the same thing both times.
然而我使用的是CS50库来获得用户输入,我说点什么,然后从用户那里获得一个字符串,并把它叫做s1,然后我说点什么,然后从用户那里获得一个字符串,并把它叫做2,这个程序的最终目的是,告诉我两次用户输入的是不是同样的东西。
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