date-arithmetic

I saw examples for C#, Java, but for C++ i cant find solution to calculate how many days between two dates. For example between 2012-01-24 and 2013-01-08 Thanks! This is one way. #include <iostream> #include <ctime> int main() { struct std::tm a = {0,0,0,24,5,104}; /* June 24, 2004 */ struct std::tm b = {0,0,0,5,6,104}; /* July 5, 2004 */ std::time_t x = std::mktime(&a); std::time_t y = std::mktime(&b); if ( x != (std::time_t)(-1) && y != (std::time_t)(-1) ) { double difference = std::difftime(y, x) / (60 * 60 * 24); std::cout << std::ctime(&x); std::cout << std::ctime(&y); std::cout <<

I am trying to calculate business days between two dates in Oracle select. I got to the point when my calculation gives most results correct for given dates (I compare it with NETWORKDAYS in excel) but sometimes it varies from 2 days to -2 days - and I don't know why... Here's my code: SELECT ((to_char(CompleteDate,'J') - to_char(InstallDate,'J'))+1) - (((to_char(CompleteDate,'WW')+ (52 * ((to_char(CompleteDate,'YYYY') - to_char(InstallDate,'YYYY'))))) - to_char(InstallDate,'WW'))*2) as BusinessDays FROM TABLE Thanks! yochim The solution, finally: SELECT OrderNumber, InstallDate, CompleteDate,

How can I change the default timezone in R? I'm working with time series. All my time series are defined in UTC time zone, but if I print a date it is always done in CET/CEST time zone. Another way to do it, without changing the whole computer time is using the setenv command like this : Sys.setenv(TZ='GMT') See this good article on changing time zone in R: http://blog.revolutionanalytics.com/2009/06/converting-time-zones.html Shortly (in case the link will be unavailable in the future): # your time string pb.txt <- "2009-06-03 19:30" # convert it to R object for London time zone pb.date <- as

I'm looking to calculate the number of months between 2 date time fields. Is there a better way than getting the unix timestamp and the dividing by 2 592 000 (seconds) and rounding up whithin MySQL? The DATEDIFF function can give you the number of days between two dates. Which is more accurate, since... how do you define a month? (28, 29, 30, or 31 days?) Month-difference between any given two dates: I'm surprised this hasn't been mentioned yet: Have a look at the TIMESTAMPDIFF() function in MySQL. What this allows you to do is pass in two TIMESTAMP or DATETIME values (or even DATE as MySQL