fips definition

In C and C + + languages, an identifier is allowed to represent a string, called a macro, which can be a constant, an expression, a string of formatting, and so on. When compiling preprocessing, all occurrences of the "macro name" in the program are substituted with the string in the macro definition, which is called "macro substitution" or "macro expansion." A macro definition is done by a macro

About the declarations and definitions of C + + variablesAs we already know, a function generally consists of two parts: the declaration part and the execution statement. The role of the Declarations section is to describe the properties of the relevant identifiers, such as the variables, functions, structs, and so on. For functions, the distinction between declarations and definitions is obvious, as explained above, the declaration of a function is a prototype of a function, and the

' Editconf.h:40:8: Error: ' std::string waitdurationg ' Previously declared Hereeditconf.cpp:56:8: error:redefinition of ' std::string timeoutpageg ' editConf.h:41:8: Error: ' std:: String Timeoutpageg ' previously declared hereeditconf.cpp:57:8: Error:redefinition of ' std::string TIMEOUTINCRG ' Editconf.h:42:8: Error: ' std::string TIMEOUTINCRG ' previously declared heremake: * * * [EDITCONF.O] Error 1Very confused, clearly defined only once!In factIn EditConf.h, there is the following code s

obtained through the system variable, directly through =, get is a null value. In fact, we follow the above understanding that the function is a command, in the shell to obtain the command return value, all need to get through the $? function scope, variable action rangeExample (test_fun2.sh): #!/bin/shecho $(uname);declare num=1000;uname(){ echo "test!"; ((num++)); return 100;}testvar(){ local num=10; ((num++)); echo $num;}uname;echo $?echo $num;testvar;echo $num; Let'

KDEV_T.H macro Definition ParsingThis header file is not much anyway, the direct reason is--met, just fix it!A variable of type dev_t is defined in Linux/types.h to hold the device number-including the main device number and the secondary device number. Dev_t is a 32-bit number, where 12 bits are used to represent the device number, and the remaining 20 bits are used to represent the secondary device number.Always do not make assumptions about whether

Macro definition Simple macroFormat: #define Identifier substitution list#define N 100int a[N];//N就是100Macros with parametersFormat: #define identifier (x1, x2, x3,...... xn) Replace list#define MAX(x, y) ((x) > (y) ? (x) : (y))Note: When the program compiles, it will replace the uppercase identifier with the original expression, so the program will increase at compile time.Advantages or DisadvantagesAdvantages① program may be a little faster② Macros

Java constant definition/** * Char type constant */private static final char char = ' A ';/** * byte type constant */private static final byte byte = 1;/** * Short Type Constant */private static final short short = 10;/** * int type constant */private static final int int = 100;/** * Long type constant */private s Tatic final Long long = 100;/** * Float type constant */private static final float float = 120f;/** * Double type constant */private static

1. class definition;2. Array of objects #includeusing namespacestd;class myfoo{private:intnum;string foostr;public:myfoo(inta,std::stringstr):num(a),foostr(str){cout} myfoo() //myfoo aSmple;如果自己写了构造函数，那么需要列出默认构造 // functions { } ~ Myfoo () { cout } }; Intmain (intargc,char*[]) { string strtmp ("I_love" ); myfoo G[3]={myfoo (1,strtmp), Myfoo (2,strtmp), Myfoo (3,strtmp)}; return 0; } 3.Foo.cpp:29:error:no m

This article is mainly on the definition of JS class or object description, the need for friends can come to the reference, I hope to help you. We know that JS is object-oriented. When it comes to object-oriented, it is inevitable to involve the concept of class. Generally, like C#,java, these strongly typed languages have a fixed syntax for defining classes. JS differs in that it can use various methods to implement its own classes and objects. The