C++ check if a date is valid

Question

is there any function to check if a given date is valid or not? I don\'t want to write anything from scratch.

e.g. 32/10/2012 is not valid and 10/10/2010 is valid

Answer 1

The boost date time class should be able to handle what you require. See http://www.boost.org/doc/libs/release/doc/html/date_time.html

Answer 2

If the format of the date is constant and you don't want to use boost, you can always use strptime, defined in the ctime header:

const char date1[] = "32/10/2012";
const char date2[] = "10/10/2012";
struct tm tm;

if (!strptime(date1, "%d/%m/%Y", &tm)) std::cout << "date1 isn't valid\n";
if (!strptime(date2, "%d/%m/%Y", &tm)) std::cout << "date2 isn't valid\n";

Answer 3

If your string is always in that format the easiest thing to do would be to split the string into its three components, populate a tm structure and pass it to mktime(). If it returns -1 then it's not a valid date.

You could also use Boost.Date_Time to parse it:

string inp("10/10/2010");
string format("%d/%m/%Y");
date d;
d = parser.parse_date(inp, format, svp);