五种宏定义

1. 源代码

   	//------------------
   
   	#define ONE_AND_ONE_REPLACEMENT test[] = {123,123}
   
   	//-------------
   
   	#define FUNCTION_REPLACE(param)  int param = 12
   
   	//--------------
   
   	#define FUNCTION_REPLACE_FUNC(x,y) (x)>(y)?(x):(y)
   
   	//----------------
   
   	#define NUM 10
   
   	#define ANY2STR(x) #x
   	#define FUNCTION_REPLACE_TO_STR(test) ANY2STR(test)
   
   	//------------
   
   	#define FUNCTION_MANY_ARGS(...) { __VA_ARGS__ }
   
   	//------------
   
   	#define DEFINE_FUNCTIONS(key) int get##key(){return 0;}
   	void set##key(int n){int t = n;}
   
   
   	DEFINE_FUNCTIONS(hello)
   	DEFINE_FUNCTIONS(world)
   	DEFINE_FUNCTIONS(this)
   	DEFINE_FUNCTIONS(is)
   
   	#undef DEFINE_FUNCTIONS
   
   	//-------------------
   
   	#define DEFINE_TWO(pre,next) void pre##  ##next(){}
   
   	DEFINE_TWO(hello,world)
   	DEFINE_TWO(frando,thethy)
   
   	#undef DEFINE_TWO
   
   	int main()
   	{
   	int ONE_AND_ONE_REPLACEMENT;
   	FUNCTION_REPLACE(hello);
   	char str[] = FUNCTION_REPLACE_TO_STR(NUM);
   	int jiejie[] = FUNCTION_MANY_ARGS(1,2,3,4,5,6);
   	}
   

2. 预编译后的代码

   	# 1 "test.cpp"
   	# 1 "<built-in>"
   	# 1 "<命令行>"
   	# 1 "/usr/include/stdc-predef.h" 1 3 4
   	# 1 "<命令行>" 2
   	# 1 "test.cpp"
   	# 30 "test.cpp"
   	int gethello(){return 0;}void sethello(int n){int t = n;}
   	int getworld(){return 0;}void setworld(int n){int t = n;}
   	int getthis(){return 0;}void setthis(int n){int t = n;}
   	int getis(){return 0;}void setis(int n){int t = n;}
   
   
   
   
   
   
   
   	void helloworld(){}
   	void frandothethy(){}
   
   
   
   	int main()
   	{
   	   int test[] = {123,123};
   	   int hello = 12;
   	   char str[] = "10";
   	   int jiejie[] = { 1,2,3,4,5,6 };
   	}
   

---

1. 纯粹的一比一替换

   	#define ONE_AND_ONE_REPLACEMENT test[] = {123,123}
   

2. 参数类型的宏

   	#define ONE_AND_ONE_REPLACEMENT test[] = {123,123}
   

3. 多参数类型的宏

   	#define FUNCTION_REPLACE_FUNC(x,y) (x)>(y)?(x):(y)
   

4. 变参数类型的宏

   	#define FUNCTION_MANY_ARGS(...) { __VA_ARGS__ }
   

5. 宏生成字符串

   	#define NUM 10
   
   	#define ANY2STR(x) #x
   
   	#define FUNCTION_REPLACE_TO_STR(test) ANY2STR(test)
   

6. 拼接类型的宏

   • 宏定义方法

     	#define DEFINE_FUNCTIONS(key) int get##key(){return 0;}
     
     	void set##key(int n){int t = n;}
     
     	DEFINE_FUNCTIONS(hello)
     
     	DEFINE_FUNCTIONS(world)
     
     	DEFINE_FUNCTIONS(this)
     
     	DEFINE_FUNCTIONS(is)
     
     	#undef DEFINE_FUNCTIONS
     

   • 多参数去空格无缝拼接

     	#define DEFINE_FUNCTIONS(key) int get##key(){return 0;}
     	void set##key(int n){int t = n;}
     
     
     	DEFINE_FUNCTIONS(hello)
     	DEFINE_FUNCTIONS(world)
     	DEFINE_FUNCTIONS(this)
     	DEFINE_FUNCTIONS(is)
     
     	#undef DEFINE_FUNCTIONS