4.如何初始化char*类型的结构体成员。

struct struct_s_BOARD {
  char * busname; 
  char * baudrate; 
};
typedef struct struct_s_BOARD s_BOARD;
s_BOARD SlaveBoard = {"0", "250K"};
这种写法会有警告，请帮忙写出一种不带警告的写法，要求不改变struct_s_BOARD 的内容

字符串字面值是常量，而 char* 可以指向可修改的内存，安全做法是将 char * busname; 改为 const char * busname;
方法1：

struct struct_s_BOARD {
  char * busname; 
  char * baudrate; 
};
typedef struct struct_s_BOARD s_BOARD;
s_BOARD SlaveBoard = {(char*)"0", (char*)"250K"};

方法2：

struct struct_s_BOARD {
  char * busname; 
  char * baudrate; 
};
typedef struct struct_s_BOARD s_BOARD;

// 使用可修改的字符串
char busname[] = "0";
char baudrate[] = "250K";
s_BOARD SlaveBoard = {busname, baudrate};

方法3：

struct struct_s_BOARD {
  char * busname; 
  char * baudrate; 
};
typedef struct struct_s_BOARD s_BOARD;

static char busname[] = "0";
static char baudrate[] = "250K";
s_BOARD SlaveBoard = {busname, baudrate};