Trouble Using Swift NSDate "timeIntervalSinceNow" -

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this question has answer here:

i've searched around , flummoxed riddle.

in swift, xcode 6.2, these lines work:

let day_seconds = 86400 let one_day_from_now = nsdate(timeintervalsincenow:86400)

but following returns error: 

let day_seconds = 86400 let one_day_from_now = nsdate(timeintervalsincenow:day_seconds)

console output:

"playground execution failed: /var/folders/4n/88gryr0j2pn318sw_g_mgkgh0000gn/t/lldb/10688/playground625.swift:24:30: error: argument 'timeintervalsincenow' in call let one_day_from_now = nsdate(timeintervalsincenow:day_seconds)"

what's going on here? why nsdate trickiness?

it's because timeintervalsincenow expect nstimeinterval double.

if do:

let day_seconds = 86400

day_second int type not method expect. when type number itself:

let one_day_from_now = nsdate(timeintervalsincenow:86400)

compiler implicit passing double, because it's method expect, ok.

the solution cancould using nstimeinterval(day_seconds) or double(day_seconds) same or when declare constant make sure it's double, example:

let day_seconds = 86400.0

or

let day_seconds: double = 86400

or

let day_seconds: nstimeinterval = 86400

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