92 Time Class Case Study-预处理器指令 #define #define pl 3.1415 #define flag 预处理器定义 o#ifdef /#ifndef o #else o #endif 0 2018, SEU. All rights reserved. 8© 2009, SEU. All rights reserved. © 2018, SEU. All rights reserved. 8 9.2 Time Class Case Study --- 预处理器指令 #define #define PI 3.1415 #define FLAG 预处理器定义 #ifdef / #ifndef #else #endif