define in and out

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

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,

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

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

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,

1) #define是预处理指令, in the compilation preprocessing simple substitution, does not make the correctness check, does not have the meaning whether correctly still to carry in, only has in the compilation has been expanded the source program only then

#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,

The use of a typedef In C/s + + language, a typedef is commonly used to define an identifier and a keyword alias, which is part of the language compilation process, but it does not actually allocate memory space, as in the case of: typedef int INT;

Define is a pre-processing command in C language. It is used for macro definition, which can improve the readability of the source code and provide convenience for programming. Pre-processing commands start with "#", for example, include commands #