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c: macro define 复杂的宏定义

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c: macro define 复杂的宏定义

 

 

 

 

一、源码

 

[root@rockylinux tmp]# cat macro_define.c 
/**
 * 宏命定义的注意事项:
 *      1、带有参数的宏,参数使用时需要写在"()"之中,这样在宏展开时不会改变设计时的运算级别,保证结果正确;
 *              举例:#define MAX_INT(x,y) (x)>(y)?(x):(y)
 *      2、多行合并为一行(代码换行):当“宏定义”内容超过一行时,在语句末尾用"\"换行,空行也要添加"\";
 *
 *      3、多行代码,可以使用"{}"和"()"。 
 *
 *
 */

#include<stdio.h>
#include<stdlib.h>


#define MAX_USER() 20


#define SAY(x,y) \
                {\
                        printf("SAY:\t%s\n", (x)); \
                        printf("SAY:\t%s\n", (y)); \
                }


#define BOOK(x,y) {\
        printf("book_name=%s, \tbook_price=%s\n", (x), (y));\
        }


#define LOOP(x) {       \
                        if((x)<=1){ exit(1);}\
                        int max = (x);\
                        for( int i=0; i<max; i++ ) printf("LOOP:\t\tcount=%d\n",i);\
                }


void msg()
{
        for(int i=0; i<MAX_USER(); i= i + 2)
        printf("%d\t\tmax_user=%d,\tcurrent=%d\n", i/2, MAX_USER(), i);
}


int main(int argc, char *argv[])
{
        LOOP(10);
        BOOK("Gangtie shi zenyang lianchengde", "23.5");
        SAY("hello world!", "hello houdini19.");
        msg();

        return 0;
}
[root@rockylinux tmp]# 
[root@rockylinux tmp]# 
[root@rockylinux tmp]# ./macro_define 
LOOP:           count=0
LOOP:           count=1
LOOP:           count=2
LOOP:           count=3
LOOP:           count=4
LOOP:           count=5
LOOP:           count=6
LOOP:           count=7
LOOP:           count=8
LOOP:           count=9
book_name=Gangtie shi zenyang lianchengde,      book_price=23.5
SAY:    hello world!
SAY:    hello houdini19.
0               max_user=20,    current=0
1               max_user=20,    current=2
2               max_user=20,    current=4
3               max_user=20,    current=6
4               max_user=20,    current=8
5               max_user=20,    current=10
6               max_user=20,    current=12
7               max_user=20,    current=14
8               max_user=20,    current=16
9               max_user=20,    current=18
[root@rockylinux tmp]# 
[root@rockylinux tmp]# 

  

 

标签:定义,macro,SAY,printf,include,define
来源: https://www.cnblogs.com/lnlidawei/p/16439539.html