I am trying to convert an int to a cstring. I've decided to read the int into a regular string via stringstream, and then read the string into a char array. The following seems to be working, but I'm wondering if I'm just getting lucky with my compiler. Does the code seem sound? Thanks!
int zip = 1234;
char zipString[30];
stringstream str;
str << zip;
str >> zipString;
cout << zipString;
You can get a C++ std::string from the stream's str() function, and an immutable C-style zero-terminated string from the string's c_str() function:
std::string cpp_string = str.str();
char const * c_string = cpp_string.c_str();
You might be tempted to combine these into a single expression, str.str().c_str(), but that would be wrong; the C++ string will be destroyed before you can do anything with the pointer.
What you are doing will work, as long as you're sure that the buffer is large enough; but using the C++ string removes the danger of overflowing the buffer. In general, it's best to avoid C-style strings unless you need to use an API that requires them (or, in extreme circumstances, as an optimisation to avoid memory allocation). std::string is usually safer and easier to work with.
stringstream.str() returned std::string&, not std::string :)
std::string for strings unless there's a compelling reason to use something else.Unless you have a specific reason that you need an array of char instead of a standard string, I'd use the latter. Although it's not strictly necessary in this case, I'd also normally use a Boost lexical_cast instead of explicitly moving things through a stringstream to do the conversion:
std::string zipString = lexical_cast<std::string>(zip);
Then, if you really need the result as a c-style string, you can use zipString.c_str() to get that (though it's still different in one way -- you can't modify what that returns).
In this specific case it doesn't gain you a lot, but consistent use for conversions on this general order adds up, and if you're going to do that, you might as well use it here too.
The std::string's c_str() member function returns a const char* (aka a C-style string).
std::string str = "world";
printf("hello, %s", str.c_str());
std::string? The latter is generally a much better option unless you're hamstrung by legacy code.std::stringcan also be indexed like an array.