The difference between #define, const, typedef#define is not defining variables, it's just for text substitution.For example:#define PI 3.1415926float Angel;angel=30*pi/180;Then, when the program is compiled, the compiler will first "#define PI 3.141
Definition:
The # define Directive
You can use the # define directive to give a meaningful name to a constant in your program. The two forms of the syntax are:
Syntax
# Define identifier token-stringopt
# Define identifier [(identifieropt,...,
What is a const?
What is a # define?
What's the use of them?
What difference do they have?
What should I do with it?
Summarize
1. What is a const?Const is a keyword (modifier) in C/s + +, which is typically used to
Thanks to http://blog.chinaunix.net/u3/111961/showart_2187819.html first
. This is an excellent article.
In the last study, we wrote a small client example, which is very simple and the header file generated by using producer-binding-tool is very
Let's look at a few examples
(1) struct{int x; int y;} Test1;
Well, define the structure test1,
test1.x and test1.y can be used in the statement.
(2) struct test {int x; int y;} Test1;
Well, define the structure test1,
test1.x and test1.y can be
A constant is an identifier (first name) of a simple value. As the name implies, the value cannot be changed during script execution (except for the so-called magic constants, they are not constants). Changshime is considered to be case sensitive.
Python timer usage + get script where absolute path + define log format test codeIf you write a script with a timer in Python, if the script also read the configuration file, then the configuration file path if you write to die, one day to change
How do I define a hyperlink to an authorized login (get nickname) in Phpwechat? Make it appear after clicking the following effect?Because of the integration of this function, in fact, this need is very simple. If you want to jump to
The examples in this article describe how classes are defined in JavaScript. Share to everyone for your reference, specific as follows:
JavaScript itself does not support object-oriented, it does not have an access control character, it does not
A constant is an identifier (first name) of a simple value. As the name implies, the value cannot be changed during script execution (except for the so-called magic constants, they are not constants). Changshime is considered to be case sensitive.
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