问题与字符串比较（strcmp）在C

Question

我是C新手。我想比较字符串，我使用'#DEFINE'和char buf [256]。 这是我的代码。

#define SRV_SHOWMENU "SRV_SHOWMENU" 
#define SRV_LOGIN_TRUE = "SRV_LOGIN_SUC" 
#define SRV_LOGIN_FAIL = "SRV_LOGIN_FAIL" 
#define SRV_REGISTER_OK = "SRV_REGISTER_SUC" 
#define SRV_REGISTER_FAIL = "SRV_REGISTER_FAIL" 
char buf[256];  // buffer for client data 
... 
... 
... 
... 
... 
... 
if(strcmp(buf,SRV_SHOWMENU) == 0 || strcmp(buf,SRV_REGISTER_FAIL) == 0) 
{ 

} 

我的C编译器告诉我systax错误 “../src/server.c:417：错误：预期表达式之前‘=’令牌”。但如果我更改为“if（strcmp（buf，SRV_SHOWMENU）== 0）”，只需进行一次比较即可。

谢谢。

Answer 1

#define后不需要使用'='符号。你可以阅读更多here。

Answer 2

正如已经说过的，取出=迹象＃定义

#define SRV_SHOWMENU "SRV_SHOWMENU" 
#define SRV_LOGIN_TRUE "SRV_LOGIN_SUC" 
#define SRV_LOGIN_FAIL "SRV_LOGIN_FAIL" 
#define SRV_REGISTER_OK "SRV_REGISTER_SUC" 
#define SRV_REGISTER_FAIL "SRV_REGISTER_FAIL" 
char buf[256];  // buffer for client data 
... 
if(strcmp(buf,SRV_SHOWMENU) == 0 || strcmp(buf,SRV_REGISTER_FAIL) == 0) 
{ 

} 

随着在=，预编译器将转向if(strcmp(buf,SRV_SHOWMENU) == 0 || strcmp(buf,SRV_REGISTER_FAIL) == 0)成

if(strcmp(buf,"SRV_SHOWMENU") == 0 || strcmp(buf,= "SRV_REGISTER_FAIL") == 0)