string char*互相转换

string to char*

https://stackoverflow.com/a/7352131/9288778

std::string str = "string";
const char *cstr = str.c_str();

Note that it returns a const char *; you aren’t allowed to change the C-style string returned by c_str(). If you want to process it you’ll have to copy it first:

std::string str = "string";
char *cstr = new char[str.length() + 1];
strcpy(cstr, str.c_str());
// do stuff
delete [] cstr;

Or in modern C++:

std::vector<char> cstr(str.c_str(), str.c_str() + str.size() + 1);
// use &chars[0] as a char*

或者https://stackoverflow.com/a/42308974/9288778

std::string str = "string";
char* chr = const_cast<char*>(str.c_str())

---

char* to string

https://stackoverflow.com/questions/8438686/convert-char-to-string-c

std::string str(buffer, buffer + length);

Or, if the string already exists:

str.assign(buffer, buffer + length);

Edit: I’m still not completely sure I understand the question. But if it’s something like what JoshG is suggesting, that you want up to length characters, or until a null terminator, whichever comes first, then you can use this:

std::string str(buffer, std::find(buffer, buffer + length, '\0'));

同理const char*转string：

const char* cc = "this is a const exp";
string s(cc, cc + strlen(cc));

char* 和const char*

const char* src = "this is a const exp";
char* ch = const_cast<char*>(src);
const char* dst = static_cast<const char*>(ch);
cout << ch << endl;
cout << dst << endl;