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

I need to use std::string to store data retrieved by fgets().

Why using fgets() when you are programming C++? Why not std::getline()?

Answer 2

const char* charPointer = "Hello, World!\n";
std::string strFromChar;
strFromChar.append(charPointer);
std::cout<<strFromChar<<std::endl;

Answer 3

I would like to mention a new method which uses the user defined literal s. This isn't new, but it will be more common because it was added in the C++14 Standard Library.

Largely superfluous in the general case:

string mystring = "your string here"s;

But it allows you to use auto, also with wide strings:

auto mystring = U"your UTF-32 string here"s;

And here is where it really shines:

string suffix;
cin >> suffix;
string mystring = "mystring"s + suffix;

Answer 4

If you already know size of the char*, use this instead

char* data = ...;
int size = ...;
std::string myString(data, size);

This doesn't use strlen.

EDIT: If string variable already exists, use assign():

std::string myString;
char* data = ...;
int size = ...;
myString.assign(data, size);

Answer 5

Most answers talks about constructing std::string.

If already constructed, just use assignment operator.

std::string oString;
char* pStr;

... // Here allocate and get character string (e.g. using fgets as you mentioned)

oString = pStr; // This is it! It copies contents from pStr to oString