const char* c_str ( ) const;
Get C string equivalent
Generates a null-terminated sequence of characters (c-string) with the same content as the string object and returns it as a pointer to an array of characters.
A terminating null character is automatically appended.
const char* data() const;
Get string data
Returns a pointer to an array of characters with the same content as the string.
Notice that no terminating null character is appended (see member c_str for such a functionality).
c_str()字符串后有' ',而data()没有
简单的const string 转void*
#include <iostream>
using namespace std;
int main()
{
const string c = "90908080";
const char* buf = c.c_str();
char* tmp = const_cast<char*> (buf);
cout<<buf<<endl;
cout<<tmp<<endl;
void* v=reinterpret_cast<void*>(tmp);
cout<<v<<endl;
cout<<(char*)(v)<<endl;
return 0;
}