Objective-C，C多个等号在一个if [重复]答案

【问题标题】：Objective-C, C multiple equality signs in one if [duplicate]Objective-C，C多个等号在一个if [重复]
【发布时间】：2014-09-01 08:58:18
【问题描述】：

我确实写了一份声明

if (sample.value > shortAverage > shortWithoutFirstAverage > longAverage) {

并且期望 sample.value > longAverage

但这不起作用，并且可能会发生 sample.value

(lldb) p (sample.value > shortAverage > shortWithoutFirstAverage > longAverage)
(bool) $13 = true
(lldb) p sample.value
(double) $14 = 0.029
(lldb) p longAverage
(double) $15 = 0.032
(lldb) p (sample.value > longAverage)
(bool) $16 = false
(lldb) p shortAverage

其他值

(double) $17 = 0.029821
(lldb) p shortWithoutFirstAverage
(double) $18 = 0.029802

看起来它被评估为

if ((sample.value > shortAverage) > (shortWithoutFirstAverage > longAverage)) {

但是如何实现所需的 if 语句呢？这样的话，(sample.value > shortAverage > shortWithoutFirstAverage > longAverage)

【问题讨论】：

标签： objective-c c

【解决方案1】：

你不能检查这样的表达式-

if (sample.value > shortAverage > shortWithoutFirstAverage > longAverage)

使用-

if ( (shortWithoutFirstAverage > longAverage) && (shortAverage > shortWithoutFirstAverage) && (sample.value > shortAverage) )

【讨论】：

【解决方案2】：

您不能像这样在 C 和相关语言中链接二元运算符，例如 >。

变化：

if (sample.value > shortAverage > shortWithoutFirstAverage > longAverage) {

到：

if (sample.value > shortAverage &&
    shortAverage > shortWithoutFirstAverage &&
    shortWithoutFirstAverage > longAverage) {

【讨论】：

【解决方案3】：

就这样吧：

if ((sample.value > shortAverage) && (shortAverage > shortWithoutFirstAverage) && (shortWithoutFirstAverage > longAverage))

【讨论】：