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1. Grammar Statement: Parameter data = 8 ' D14; ' Define Data 8 ' D14 Use:Data ' Data 2. Scope Parameter the file that acts on the Declaration, ' define reads from the compiler until the end of the compilation is valid, or the ' undef command invalidates it. If you want parameter or ' define to work on the entire project, you can write the following declaration i

In general, we define a constant using # define, #define的本质是文本替换, for example, # define INT_PTR int*, when we use a int_ptr,int_ptr a, B, which is equivalent to an INT * A, A, a, b; That is, define a pointer variable A and integer variable B, which is a common scenario for #

1 NO parameter macro definitionThe macro name of the parameterless macro is not followed by a parameter.The general form of its definition is:#define Identifier stringWhere the "#" indicates that this is a preprocessing command. All that begin with "#" are pre-processing commands. "Define" defines the command for the macro. "Identifier" is the name of the macro defined. A "string" can be a constant, an expr

Note: Define cannot be defined in a class, and the const must be defined in a class, and the const must be accessed by the class name:: Variable name 1. Const is used for class member variable definition once defined and cannot change its value. Define defines global constants that can be accessed anywhere.2, define can not be defined in the class and Const.3. C

Original article address: Http://blog.csdn.net/kindazrael/article/details/8108868 In C, Preprocessor is a powerful tool that makes your code easier to read and modify. With preprocessing code, you can redefine a part of the code to make your code more suitable for your style. Preprocessor is processed in advance before the code is compiled. The pre-processing code starts with a pound sign.1. About #define #defineDeclarations are mainly used to assign

#define宏定义在C系开发中可以说占有举足轻重的作用. The underlying framework does not have to say, in order to compile optimization and convenience, as well as cross-platform capabilities, macros are heavily used, it can be said that the bottom of development left define will be unable to move. When developing at a higher level, we put more emphasis on business logic and seem to have little use and reliance on macros.But the ben

1. Brief example of enum enum useWhen writing a program, we often need to associate an optional set of alternative properties for an object. For example, the students ' grades a,b,c,d and so on, the weather is sunny, cloudy, rainy and so on.More commonly, opening a file may have three statuses: input, output, and append. A typical practice is to define 3 constants, namely:const int input = 1;const int output = 2;const int append = 3;Then, call the fol

Constants must be defined before they are used, or the program execution will fail. Use the Define () function in the PHP tutorial to define constants. 1. Syntax format: define ("Constant name", "Constant value"); For example: Define ("php360", "Perfect php"); Here's an example: The

1 , Syntax Statement: Parameter xx = YY;'Define XX YY Usage: Xx'Xx2 , Scope Parameter The file to be declared; 'Define It is valid from the time the compiler reads this instruction to the end of compilation, or 'Undef Command to make it invalid. If you want Parameter Or 'Define For the entire project, you can write the following statement into a

What is the difference between a variable and one? define('SOMETHING', true);andconst SOMETHING = true; Performance or otherwise? Reply content: What is the difference between a variable and one? define('SOMETHING', true);andconst SOMETHING = true; Performance or otherwise? Baidu can solve the problem, the landlord did not self-study spirit? 【问】在php中定义常量时,const与d