zero

Is 0 a decimal literal or an octal literal?

由 半腔热情 提交于 2019-11-26 11:37:27
Zero is always zero, so it doesn't matter. But in a recent discussion with my friend he said that octal literals are almost unused today. Then it dawned upon me that actually almost all integer literals in my code are octal, namely 0 . Is 0 an octal literal according to the C++ grammar? What does the standard say? Yes, 0 is an Octal literal in C++. As per the C++ Standard: 2.14.2 Integer literals [lex.icon] integer-literal: decimal-literal integer-suffixopt octal-literal integer-suffixopt hexadecimal-literal integer-suffixopt decimal-literal: nonzero-digit decimal-literal digit octal-literal:

Python Force python to keep leading zeros of int variables

由 别说谁变了你拦得住时间么 提交于 2019-11-26 11:35:14
问题 Below is a section of code which is part of a functional decryption and encryption program. while checkvar < maxvar: # is set to < as maxvar is 1 to high for the index of var #output.append(\"%02d\" % number) i =ord(var[checkvar]) - 64 # Gets postional value of i i = (\"%02d\" % i) if (checkvar + 1) < maxvar: j =ord(var[(checkvar + 1)]) - 64 # Gets postional value of i j = (\"%02d\" % j) i = str(i) + str(j) #\'Adds\' the string i and j to create a new i li.append(int(i)) checkvar = checkvar +

PHP prepend leading zero before single digit number, on-the-fly [duplicate]

由 社会主义新天地 提交于 2019-11-26 09:15:01
问题 This question already has an answer here: Formatting a number with leading zeros in PHP 14 answers PHP - Is there a quick, on-the-fly method to test for a single character string, then prepend a leading zero? Example: $year = 11; $month = 4; $stamp = $year.add_single_zero_if_needed($month); // Imaginary function echo $stamp; // 1104 回答1: You can use sprintf: http://php.net/manual/en/function.sprintf.php <?php $num = 4; $num_padded = sprintf("%02d", $num); echo $num_padded; // returns 04 ?> It

&#39;property: 0&#39; or &#39;property: 0px&#39; in CSS?

由 百般思念 提交于 2019-11-26 08:22:28
问题 I\'ve seen this notation used a lot, and I was wondering, is there is any notable difference between these two notations? element#id { property: 0; } and element#id { property: 0px; } I use property: 0px; all the time, as I find it cleaner looking, but I\'m not really sure if the browser interprets 0px differently than 0 . Does anyone know which one is better or correct? 回答1: Unit identifiers are optional , but there is no noted performance increase (although you are saving two characters).

MySQL monthly Sale of last 12 months including months with no Sale

由 五迷三道 提交于 2019-11-26 08:19:31
问题 SELECT DATE_FORMAT(date, \"%b\") AS month, SUM(total_price) as total FROM cart WHERE date <= NOW() and date >= Date_add(Now(),interval - 12 month) GROUP BY DATE_FORMAT(date, \"%m-%Y\") This query displaying result for only existing month. I need all 12 months sales. Output : \"month\" \"total\" -------------- \"Jun\" \"22\" \"Aug\" \"30\" \"Oct\" \"19\" \"Nov\" \"123\" \"Dec\" \"410\" Required Output : \"month\" \"total\" -------------- \"Jan\" \"0\" \"Feb\" \"0\" \"Mar\" \"0\" \"Apr\" \"0\"

negative zero in python

由 不羁的心 提交于 2019-11-26 07:47:14
问题 I encountered negative zero in output from python; it\'s created for example as follows: k = 0.0 print(-k) The output will be -0.0 . However, when I compare the -k to 0.0 for equality, it yields True. Is there any difference between 0.0 and -0.0 (I don\'t care that they presumably have different internal representation; I only care about their behavior in a program.) Is there any hidden traps I should be aware of? 回答1: Check out : −0 (number) in Wikipedia Basically IEEE does actually define a

h:inputText which is bound to Integer property is submitting value 0 instead of null

由 跟風遠走 提交于 2019-11-26 04:53:43
问题 We are using a h:inputText in a JSF page which is bound to an Integer property (and thus can accept null ). When there is no value written in the h:inputText , the form is submitting a 0 instead of null . We are using Trinidad 1.2.2 and Tomcat 6.0.20 (we also tried with Tomcat 6.0.14 as we read that this could happen with certains Tomcat versions). How is this caused and how can I solve it? 回答1: This "feature" was result of a bugfix in EL which was introduced as per Tomcat 6.0.16. As per

Why is JSON invalid if an integer begins with a leading zero?

由 懵懂的女人 提交于 2019-11-26 03:56:42
问题 I\'m importing some JSON files into my Parse.com project, and I keep getting the error \"invalid key:value pair\". It states that there is an unexpected \"8\". Here\'s an example of my JSON: } \"Manufacturer\":\"Manufacturer\", \"Model\":\"THIS IS A STRING\", \"Description\":\"\", \"ItemNumber\":\"Number12345\", \"UPC\":083456789012, \"Cost\":\"$0.00\", \"DealerPrice\":\" $0.00 \", \"MSRP\":\" $0.00 \", } If I update the JSON by either removing the 0 from \"UPC\":083456789012, or converting

Is it safe to check floating point values for equality to 0?

由 走远了吗. 提交于 2019-11-26 03:34:05
问题 I know you can\'t rely on equality between double or decimal type values normally, but I\'m wondering if 0 is a special case. While I can understand imprecisions between 0.00000000000001 and 0.00000000000002, 0 itself seems pretty hard to mess up since it\'s just nothing. If you\'re imprecise on nothing, it\'s not nothing anymore. But I don\'t know much about this topic so it\'s not for me to say. double x = 0.0; return (x == 0.0) ? true : false; Will that always return true? 回答1: It is safe

How to make number input area initially empty instead of 0 or 0.00?

由 佐手、 提交于 2019-11-26 02:59:07
问题 I have an input place that should get a number. I want it to be displayed as empty. However when I run my program, I get 0 or 0.00 as default. How can I make it empty? 回答1: This will happen if you bound the value to a primitive instead of its wrapper representation. The primitive int always defaults to 0 and the primitive double always defaults to 0.0 . You want to use Integer or Double (or BigDecimal ) instead. E.g.: public class Bean { private Integer number; // ... } Then there are two
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