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// RUN: %target-run-simple-swift( -Xfrontend -disable-availability-checking %import-libdispatch -parse-as-library)
// REQUIRES: executable_test
// REQUIRES: concurrency
// REQUIRES: libdispatch
// rdar://76038845
// REQUIRES: concurrency_runtime
// UNSUPPORTED: back_deployment_runtime
import Dispatch
func fib(_ n: Int) -> Int {
var first = 0
var second = 1
for _ in 0..<n {
let temp = first
first = second
second = temp + first
}
return first
}
@available(SwiftStdlib 5.1, *)
func asyncFib(_ n: Int) async -> Int {
if n == 0 || n == 1 {
return n
}
let first = detach {
await asyncFib(n - 2)
}
let second = detach {
await asyncFib(n - 1)
}
// Sleep a random amount of time waiting on the result producing a result.
await Task.sleep(UInt64.random(in: 0..<100) * 1_000_000)
let result = try! await first.get() + second.get()
// Sleep a random amount of time before producing a result.
await Task.sleep(UInt64.random(in: 0..<100) * 1_000_000)
return result
}
@available(SwiftStdlib 5.1, *)
func runFibonacci(_ n: Int) async {
var result = await asyncFib(n)
print()
print("Async fib = \(result), sequential fib = \(fib(n))")
assert(result == fib(n))
}
@available(SwiftStdlib 5.1, *)
@main struct Main {
static func main() async {
await runFibonacci(15)
}
}
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