swift - while循环，找到最接近零的值

Question

我正在尝试找到使 IRDPenaltyCalculation 等于 0 的比率。我可以使用 UISlider 获取该值。但我想计算该值，以便我可以设置 UISlider 最小值。下面的代码给出了错误的比率，并且直到 IRDPenaltyCalculation 等于 0 时才会运行。我觉得我忽略了一个简单的步骤。

var IRDPenaltyCalculation = IRDPenalty(IRDComparisonRate: Double(comparisonRate / 100), mtgBalance: mortgageBalance, mthsToMaturity: Double(monthsToMaturity), discount: Double(mortgageRateDiscount), currentRate: rate)

while IRDPenaltyCalculation > 0 {
    rate -= 0.01

    print("Rate: \(rate)")

    IRDPenaltyCalculation = IRDPenalty(IRDComparisonRate: Double(comparisonRate / 100), mtgBalance: mortgageBalance, mthsToMaturity: Double(monthsToMaturity), discount: Double(mortgageRateDiscount), currentRate: rate)

    print("IRD: \(IRDPenaltyCalculation)")
    rateLabel.text =  String(IRDPenaltyCalculation)

}

Answer 1

尝试这样的事情:

while IRDPenalty(IRDComparisonRate: Double(comparisonRate / 100), mtgBalance: mortgageBalance, mthsToMaturity: Double(monthsToMaturity), discount: Double(mortgageRateDiscount), currentRate: rate) > 0 {
    rate -= 0.01
}
print("Rate: \(rate)")

var IRDPenaltyCalculation = IRDPenalty(IRDComparisonRate: Double(comparisonRate / 100), mtgBalance: mortgageBalance, mthsToMaturity: Double(monthsToMaturity), discount: Double(mortgageRateDiscount), currentRate: rate)

print("IRD: \(IRDPenaltyCalculation)")
rateLabel.text =  String(IRDPenaltyCalculation)