Question

我试图为类似于高/低游戏的游戏制作if else语句。当您单击该按钮时，似乎该语句正在跳过if NewNumber <= oldNumber部分并直接转到其他部分。它应检查旧整数的新整数，看它是高还是低。只是做了一会儿，所以我不确定我做错了什么

//Lower Button
@IBAction func lowerButton(sender: AnyObject) {
    var newNumber = randomIntBetween(2, high: 26)
    var oldNumber: Int?

    func lowerNumber() -> Int {
        if newNumber <= oldNumber {
            correctWrongLabel.text = "You Were Correct!"
            scoreLabel.text = "Score: \(countWin++)"
        } else {
            correctWrongLabel.text = "You Were Wrong!"
            scoreLabel.text = "Score: \(countLose)"
        }
        return newNumber
    }

    let newValue = lowerNumber()
    randomIntLabel.text = "\(newValue)"
}

Answer 1

您正在将Int值与nil类型Int?的值进行比较

var newNumber = 10
var oldNumber: Int?

if newNumber <= oldNumber {
    print("<=")
} else {
    print("Not <=")
}

结果

Not <=

在Swift中，Int不是<=而不是nil，这就是执行else分支的原因。

建议

lowerNumber是一种非常奇怪的方法：

它不需要参数
它返回最小值
并且还执行一些操作

我建议你把它改成像这样的东西

func updateUI(old: Int, new: Int) {
    if new <= old {
        correctWrongLabel.text = "You Were Correct!"
        scoreLabel.text = "Score: \(countWin++)"
    } else {
        correctWrongLabel.text = "You Were Wrong!"
        scoreLabel.text = "Score: \(countLose)"
    }
}

然后，在您的代码中，您需要获得2个值之间的最小值，只需使用min

if let oldNumer = oldNumber {
    let minimum = min(newNumber, oldNumber)
}

Swift如果else语句没有按预期工作

1 个答案:

建议