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
1. Define (that is, host variable)The main role of the host variable is to act as an alternative variable, a medium in which the host environment can interact with Oracle . When you define a host variable by define, you must specify the variable
#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,
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
When you need to perform complex data analysis in an Excel worksheet, many formulas are often written. However, these complex formulas are a headache. If you are good at using names when writing formulas, this greatly improves the readability of
#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,
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
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,...,
: This article mainly introduces the difference between const and define in php (supplement). If you are interested in PHP tutorials, refer to it. A constant is the identifier (name) of a simple value ). As its name implies, this value cannot be
The content source of this page is from Internet, which doesn't represent Alibaba Cloud's opinion;
products and services mentioned on that page don't have any relationship with Alibaba Cloud. If the
content of the page makes you feel confusing, please write us an email, we will handle the problem
within 5 days after receiving your email.
If you find any instances of plagiarism from the community, please send an email to:
info-contact@alibabacloud.com
and provide relevant evidence. A staff member will contact you within 5 working days.