/***********************************************************
@Execise: 
    統(tǒng)計字符串中單詞的數(shù)目
@Notice:
    1. NSRegularExpression 來自 Foundation
    2. Swift 的異常捕捉寫法很另類(哈哈哈涩赢，任性咯)：
        與大多數(shù)語言相比撕予，執(zhí)行可能出現(xiàn)異常的代碼塊用do稚配，然后try放在代
        碼塊中可能產(chǎn)生異常的代碼開頭，catch用來捕獲異常
    3. 判斷是否單詞的正則表達式："\\w+"
***********************************************************/

import Foundation

func wordCount(_ string: String)->Int{
    do {
        //構(gòu)造正則表達式
        let regular = try NSRegularExpression(pattern: "\\w+", options: .caseInsensitive)
        let matches = regular.matches(in: string, options: [], range: NSMakeRange(0, string.characters.count))
        // 打印出所有單詞
        // for result in matches {
        //     print((string as NSString).substring(with: result.range))
        // }
        return matches.count
    } catch _ {
        return 0
    }
}

let string = "A nonprofit organization (NPO) is an organization that uses surplus revenues to achieve its goals rather than distributing them as profit or dividends. The goals of an NPO are always to change or improve a social issue. NPOs use the model of a double bottom line in that furthering their cause is more important than making a profit though both are necessary to the organization's success. Although nonprofit organizations are permitted to generate surplus revenues, they must be retained by the organization for its self-preservation, expansion, or plans. NPOs have controlling members or a board of directors. Many have paid staff including management, whereas others employ unpaid volunteers and even executives who work with or without compensation (occasionally nominal). Where there is a token fee, in general, it is used to meet legal requirements for establishing a contract between the executive and the organization. Designation as a nonprofit does not mean that the organization does not intend to make a profit, but rather that the organization has no owners and that the funds realized in the operation of the organization will not be used to benefit any owners. The extent to which an NPO can generate surplus revenues may be constrained or use of surplus revenues may be restricted."

print(wordCount(string)) // 211