extern引用外部全局变量defineSIZE20inta[SIZE];//经常这么用宏替换definePrint(My_var)printf("%d",My_var)definemax(x,y)x>y?x:y如果一行放不下可以加\换行继续字符串作为宏参数defineSTR"cxc"用宏连接字符串definejoin(a,b)abprintf("%d\n",strlen(join("cxc","as")));//输出5ifndefblock等价于if!defineblockifdefblock等价于ifdefinedblock条件宏举例：include<stdio.h&gt...