The functions shown below are examples of measuring elapsed time in Swift. The sleep function is used to delay the code execution for 4 seconds. Consequently, the elapsed time for each example is approximately 4 seconds.
import Foundation
func exampleOne() {
let tic = DispatchTime.now().uptimeNanoseconds
sleep(4)
let toc = DispatchTime.now().uptimeNanoseconds
print("Elapsed time is \((toc - tic) / 1_000_000_000) seconds")
}
func exampleTwo() {
let tic = CFAbsoluteTimeGetCurrent()
sleep(4)
let toc = CFAbsoluteTimeGetCurrent()
print("Elapsed time is \(toc - tic) seconds")
}
func exampleThree() {
let tic = Date.now
sleep(4)
let toc = tic.timeIntervalSinceNow.magnitude
print("Elapsed time is \(toc) seconds")
}
func exampleFour() {
let clock = ContinuousClock()
let result = clock.measure {
sleep(4)
}
print("Elapsed time is \(result)")
}
exampleOne()
exampleTwo()
exampleThree()
exampleFour()
Running the above code in a file named elapsedtime.swift gives the following output:
$ swiftc elapsedtime.swift; ./elapsedtime
Elapsed time is 4 seconds
Elapsed time is 4.005115985870361 seconds
Elapsed time is 4.005129098892212 seconds
Elapsed time is 4.003226656 seconds
