1、结构体 转 void*
struct A {};
A a;
void * b = (void *)&a;
2、const void* 转 void*
const void* pConstVoid;
(1) 首先用const_cast转换将const void*的const属性去掉
void* pChar = const_cast<void*>(pConstVoid);
(2) 用static_cast给void* 变量加上const属性,并转换成char*
const char* p = static_cast<const char*>(pChar);
3、const char* 转 string
const char* pConstVoid
string = pConstVoid;
4、string 转 char*
string str="wred";
char *p=str.c_str();
5、char*转 string
string s(char *);