Question

Is it possible to do this

std::string str(const char* s)
{  
     return std::string(s);
} 

int main() {  
    char* strz = (char*)str("asd").c_str();  
}  

Instead of:

int main(){  
    std::string temp = str("asd");  
    char* strz = (char*)temp.c_str();  
}

I know it should be const char* strz but I need it only within block of code(and without new/delete). After returning string from method it look for reference(if cant find it, deletes string) and then calls c_str(). I have a lot of char’s(independent from me) and I could use second solution but it takes too much code.

Answer 1

If you use your second option –

std::string temp = str("asd");
char* strz = (char*)temp.c_str();

You’re possibly running into undefined behavior. It’s illegal to modify the contents of strz. You’ll have to use strcpy to get a mutable array of char‘s. Your first isn’t any better either, moreover, it’s redundant, since you can directly use string‘s constructor.

Anyway, to get a char* from a string you can do:

char* get(const std::string& str)
{
   char* ret = new char[str.length() + 1]();
   strcpy(ret,str.c_str());
   return ret;
}

You’ll have to delete[] the memory yourself when you’re done with it.