Convert char* to string C++

Question

I know the starting address of the string(e.g., char* buf) and the max length int l; of the string(i.e., total number of characters is less than or equ

Answer 1

There seems to be a few details left out of your explanation, but I will do my best...

If these are NUL-terminated strings or the memory is pre-zeroed, you can just iterate down the length of the memory segment until you hit a NUL (0) character or the maximum length (whichever comes first). Use the string constructor, passing the buffer and the size determined in the previous step.

string retrieveString( char* buf, int max ) {

    size_t len = 0;
    while( (len < max) && (buf[ len ] != '\0') ) {
        len++;
    }

    return string( buf, len );

}

If the above is not the case, I'm not sure how you determine where a string ends.

Answer 2

Use the string's constructor

basic_string(const charT* s,size_type n, const Allocator& a = Allocator());

EDIT:

OK, then if the C string length is not given explicitly, use the ctor:

basic_string(const charT* s, const Allocator& a = Allocator());

Answer 3

std::string str;
char* const s = "test";

str.assign(s);

string& assign (const char* s); => signature FYR

Reference/s here.

Answer 4

char *charPtr = "test string";
cout << charPtr << endl;

string str = charPtr;
cout << str << endl;

Answer 5

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'));