/** 2, please explain the meaning of the characters ' \ ' in Java, what is the role?*Answer* In Java the backslash ' \ ' represents the meaning of the escape character, which is a marker** When the compiler reads this tag, it knows that the next character is not an ordinary character, but a translated character.* It will operate based on the meaning of the escape
PYTHON Specifies special variables/methods using underscores as variable prefixes and suffixes.There are four main cases1.1. Object # Public2. __object__ # Special, Python system use, user should not define like it3. __object # Private (name mangling during runtime)4. _object # Obey Coding Convention, consider it as privateCore style: Avoid using underscores as the start of variable names .Because underscores have special meanings for the interpreter and are symbols used by the built-in, we reco
;! function () {} (); ;! What's the use?Go from grammar to open. The semicolon in JavaScript indicates the end of the statement, plus at the beginning. It may be for compression and other methods to cut, indicating a new statement starts. So, let's say it's in a separate JS file. The beginning of the semicolon is no matter what the meaning, can be deleted.An exclamation point is a logical operator, which is "non", and is commonly written if (!true) {}
The meaning of the square operation of the adjacency matrix of a direction graph
This is an assignment in the first chapter of graph theory algorithm application. Now, the linear algebra is too bad. Hey
First code:
#include
The title requires the matrix to be written after the square of the adjacency matrix of the direction graph, then say the meaning of it, write code nearly one hours, want to
One, what is a single case mode? 1, meaningAs an object's creation pattern, the singleton pattern ensures that a class has only one instance, and instantiates it and provides it globally to the entire system. Instead of creating an instance copy, it returns a reference to an instance stored within a singleton class.2, the single example mode of the three points:(1). A static member variable is required to hold a unique instance of the class:private static $_instance;(2). Constructors and cloning
1 Preface
In many foreign computer books and some of the third open source software demo often use two English words foo,bar. What the hell does that mean? From the IT life of the cock Silk circle simple These two words to now I still do not know the true meaning of these two words, today it is necessary to check the summary.
2 explanation on Wikipedia
Original:
The terms foobar, Foo, bar, Baz and Qux are sometimes, used as placeholder names (also
The meaning of Hibernate's generator attributeThis article describes the meaning of Hibernate's generator attribute.The generator attribute has 7 classes, and this article briefly describes the meaning and usage of these 7 classes.Hibernate's Generator attribute has 7 classes, this article briefly describes the meaning
The meaning of living out of lifeMisery itself is meaningless, but we can give it meaning through our own response to suffering.From this book, from the Frankel of life in Auschwitz, I learned that the ultimate freedom of humanity is the freedom to choose one's attitude and way of life in any situation!I also think of "Xiangtalan" in a paragraph: "Even if the shackles of the body, a blood-stained, isolated
The basic metacharacter set of the Regular Expression and Its Meaning (lower). The character set of the regular expression.
Pattern \ {n \}
Used to match the occurrence times of the previous pattern. N is the number of times
All tools
Pattern \ {n, \} m
The meaning is the same as above, but the minimum number of times is n.
All tools
Pattern \ {n, m
Today to share with you what is the key word. Mainly divided into 5 parts, including: Why is called the keyword, the keyword itself is how to come to the name, and then talk about the relationship between keywords and search engines, keyword classification of what, when the best time to implant keywords, the pros and cons of keywords.
First let's look at what is called the keyword.
The source of this name of the key words we first learn from a number of knowledge encyclopedia. The Chinese name
Reprinted from: http://www.cnblogs.com/davygeek/p/5670212.htmlLearn to write a script today encountered some variables do not know, here do the next record.
Variable
Meaning
$
File name of the current script
$n
Arguments passed to the script or function. N is a number that represents the first few parameters. For example, the first parameter is $ $, and the second argument is a $
1. Create a simple script variable:Vim variable2. Modify the contents as follows:#!/bin/SHEcho "number:$#"Echo "scname:$0"Echo "First : $"Echo "second:$2"Echo "Argume:[email protected]"Echo "Show Parm list:$*"Echo "Show Process id:$$"Echo "Show Precomm stat: $?"3. Execute the Script./variableThe meaning of some parameters in a Linux shell script: $# is the number of arguments passed to the script. The name of the script is the first parameter that is
please explain below The whole line of code in the Shell script that starts with if, have you seen the application scenario ?if (kill-0 $pid 2>/dev/du11) then echo "Oldboy" Else echo "Oldgirl" fiInterview question: Please explain the meaning of if (kill-0 $pid 2>/dev/null) code?if (kill-0 $pid 2>/dev/null) then echo "Oldboy" Else echo "Oldgirl" fiThe old boy answers the main points:
kill-0 $pid 0 means not to send any signal to the PID correspon
Http://wenku.baidu.com/link?url=9Q9VU54XuvlN77urP1zwOLVMMrS2EFNx4HcvFizdPl-zQy3K_ Ipd3o-mdu4sbihezumnq0blbwhusuaol_y6quvkxtgjiaem9gq9i-jb5_e Shell in the condition to determine if in the-Z to-D meaning 2011-09-05 [-a file] if the file The existence is true. [-B file] True if file exists and is a block special file. [-C file] True if file exists and is a word special. [-D file] True if file exists and is a directory. [-E File] True if file exists. [-F
Original URL: http://dadekey.blog.51cto.com/107327/119938let's start by writing a simple script that will explain the meaning of each variable after execution .# Touch Variable# VI VariableThe script reads as follows:#!/bin/shecho "number:$#"echo "Scname:$0"echo "First: $ $"echo "Second:$2"echo "Argume:[email protected]"echo "Show Parm list:$*"echo "Show Process id:$$"echo "Show Precomm stat: $?"Save Exit assigning script Execution Permissions# chmod
files for each of the devices it can guide in this directory during the installation process. This means that you rarely need to create it yourself.As hardware moves out of the computer, the names become more blurred. Fortunately, today's high-grade software blocks on Linux use easy-to-understand names for history and hardware. For example, well, Pango (http://www.pango.org/) is one of them.If you are interested in these things, then I suggest you read the grand, but some of US English history-
and profound, the whole such abbreviation is too professional, people are around dizzy. It is easier to understand from the English explanation or the Chinese full name.Pointer array: Array of pointers, which is used to store pointers to arrays, which are arrays of elements that are pointersArray pointer: A pointer to an array, which is a pointer to the arrayAlso note the differences in their usage, as illustrated below.int* a[4] Pointer array: The elements in array A are all int pointers (if t
#!/bin/bash#Created by Ley on 2014-11-14#Testing the Paramtersecho "The Compleate list is%s\n" "$$"echo "The Compleate list is%s\n" "$!"echo "The Compleate list is%s\n" "$?"echo "The Compleate list is%s\n" "$*"echo "The Compleate list is%s\n" "[Email protected]"echo "The Compleate list is%s\n" "$#"echo "The Compleate list is%s\n" "$ $"echo "The Compleate list is%s\n" "$"echo "The Compleate list is%s\n" "$ $"the meaning of shell variable $#,[email prot
Original URL: http://www.cnblogs.com/fhefh/archive/2011/04/15/2017613.htmlThe meaning of shell variable $#,[email protected],$0,$1,$2 in Linux is explained:Variable Description:$$The PID of the shell itself (ProcessID)$!PID of the Shell's last running background process$?End code of the last Run command (return value)$-Flag at a glance using the SET command$*All parameter lists. such as "$*" in the Case of "" ", in the form of" $ $ ... $n "output all
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