convert a char* to std::string

Question

I need to use an std::string to store data retrieved by fgets(). To do this I need to convert the char* return value from fgets(

Answer 1

std::string has a constructor for this:

const char *s = "Hello, World!";
std::string str(s);

Note that this construct deep copies the character list at s and s should not be nullptr, or else behavior is undefined.

Answer 2

char* data;
std::string myString(data);

Answer 3

I've just been struggling with MSVC2005 to use the std::string(char*) constructor just like the top-rated answer. As I see this variant listed as #4 on always-trusted http://en.cppreference.com/w/cpp/string/basic_string/basic_string , I figure even an old compiler offers this.

It has taken me so long to realize that this constructor absolute refuses to match with (unsigned char*) as an argument ! I got these incomprehensible error messages about failure to match with std::string argument type, which was definitely not what I was aiming for. Just casting the argument with std::string((char*)ucharPtr) solved my problem... duh !

Answer 4

Not sure why no one besides Erik mentioned this, but according to this page, the assignment operator works just fine. No need to use a constructor, .assign(), or .append().

std::string mystring;
mystring = "This is a test!";   // Assign C string to std:string directly
std::cout << mystring << '\n';

Answer 5

char* data;
stringstream myStreamString;
myStreamString << data;
string myString = myStreamString.str();
cout << myString << endl;

Answer 6

Pass it in through the constructor:

const char* dat = "my string!";
std::string my_string( dat );

You can use the function string.c_str() to go the other way:

std::string my_string("testing!");
const char* dat = my_string.c_str();