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:
/header file content
Macro definition in C # define usage,
# Define is a macro definition Command provided in C language. Its main purpose is to provide programmers with some convenience in programming and improve the program running efficiency to a certain extent,
[Switch] DEFINE introduction and multi-row macro definition in C language, define multiple lines
[Go] DEFINE introduction and multi-row macro definition in C LanguageTo write a good C language, a beautiful macro definition is very important. Macro
Macro definition ' DefineRepresents a string with a specified identifier (that is, the name), which is in its general form:' Define identifier (macro name) string (macro content)such as: ' Define signal stringIts function is to specify the
1. Simple macro definition
#define Identifier substitution list (alternate list can be number, string literal, punctuation, operator, identifier, keyword, Word constants quantity.) Note: The substitution list is nullable.
#define N = 1
Recently in the cloud Platform for the initial code architecture, encountered a constant definition speed comparison problem, so do a comparison.
The APC extension for PHP is described in the following paragraph in the PHP
#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,
To write a good C language, a beautiful macro definition is very important. Macro definitions can help us prevent errors, improve code portability and readability, and more.In the software development process, there are often common or common
#defineThe command #define defines an identifier and a string. Each time the identifier is encountered in the source program, it is substituted with a defined string. The ANSI standard defines an identifier as a macro name and replaces the process
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
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