从参考：
https://developer.apple.com/library/prerelease/ios/documentation/General/Reference/SwiftStandardLibraryReference/index.html测试
原文链接：https://www.f2er.com/swift/320408.htmlvar string = String(count: 5,repeatedValue: "a") // string is "aaaaa"
我收到这个错误：
Playground execution Failed: error: :5:14: error: could not find an overload for ‘init’ that accepts the supplied arguments
var string = String(count: 5,repeatedValue: “a”)
这实际上有效吗？
