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
#define是C语言中提供的宏定义命令, the main purpose is to provide programmers with certain convenience in programming, and to a certain extent, improve the efficiency of the program, but students often do not understand the nature of the command in learning,
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,...,
There are many places in the C language where macro definitions are used, such as in header files to prevent header files from being repeatedly included:
#ifndef ctest_header_h
#define CTEST_HEADER_H
/header file content
#endif
Many macro
Jency LeeLinks: http://www.cnblogs.com/Jency/articles/C_Cplusplus_define.html1. Simple define Definition #define MaxTime + A simple maxtime is defined, which represents 1000 if you write in the program if (i Compiler replaces maxtime with 1000
#define是C语言中提供的宏定义命令, the main purpose is to provide programmers with certain convenience in programming, and to a certain extent, improve the efficiency of the program, but students often do not understand the nature of the command in learning,
As we all know, in PHP (PHP 4 and later), we can use the function define () to define constants, for example:
However, after PHP 5.3.0, in addition to using function define (), we can also use the PHP keyword const to define constants.
For example:
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
#define是C语言中提供的宏定义命令, the main purpose is to provide programmers with a certain degree of convenience in programming, and to a certain extent to improve the efficiency of the program, but students often do not understand the nature of the command,
Http://blog.sina.com.cn/s/blog_686188ef0100klku.html#define是C语言中提供的宏定义命令, the main purpose is to provide programmers with certain convenience in programming, and to a certain extent, improve the efficiency of the program, but students often do not
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