从非投掷方法中捕捉错误。

Question

迅捷

Swift中的整数是可以的。它们不能像Doubles那样无限，以为。它们有一个极限。超过这个极限会导致崩溃。

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证据A Int(10000000000000000000) error: integer literal '10000000000000000000' overflows when stored into 'Int'

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附表B Int(pow(Double(1000000000), Double(10))) Fatal error: Double value cannot be converted to Int because the result would be greater than Int.max

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我天真地想："嘿，这是一个致命的错误。我可以用做、抓块来抓到这个错误吗？" 不可以

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证据C

do {
    Int(pow(Double(1000000000), Double(10)))
} catch {
    print("safety net")
}
print("good?")

warning: 'catch' block is unreachable because no errors are thrown in 'do' block Fatal error: Double value cannot be converted to Int because the result would be greater than Int.max

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哦，是的。是的，没错！我忘了加 尝试 不对

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证据D

do {
    try Int(pow(Double(1000000000), Double(10)))
} catch {
    print("safety net")
}
print("good?")

warning: no calls to throwing functions occur within 'try' expression warning: 'catch' block is unreachable because no errors are thrown in 'do' block Fatal error: Double value cannot be converted to Int because the result would be greater than Int.max

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这到底是怎么回事？

谁能给我解释一下？我真的很想能够 catch 这样的错误。非常感谢，这将是一个巨大的帮助!

Answer 1

你可以使用 init(exactly:) 构造函数，它不会抛出错误，但如果值过大，它将返回nil。

guard let value = Int(exactly: pow(Double(1000000000), Double(10))) else {
    //error handling
}