1、##
#define SOFTWARE_VERSION "Software：V1.00"
#define HARDWARE_VERSION "Hardware：V1.00"
#define SYSTEM_VERSION SOFTWARE_VERSION##" "##HARDWARE_VERSION
2、空格
1》拼接两个宏定义
#define SOFTWARE_VERSION "Software：V1.00"
#define HARDWARE_VERSION "Hardware：V1.00"
#define SYSTEM_VERSION SOFTWARE_VERSION HARDWARE_VERSION
2》拼接一个宏定义和一个字符串
#define SOFTWARE_VERSION "Software：V1.00"
#define SYSTEM_VERSION SOFTWARE_VERSION "Hardware：V1.00"
