如果声明与&&在测试第二个条件之前，第一个条件必须为真 [英] If statement with && where the first condition needs to be true before testing the second

问题描述

很抱歉，如果这是重复的，但我甚至想不出一种搜索方式。我不确定要问这个问题的术语，所以我只会解决我的问题。

Sorry if this is a duplicate, but I can't even think of a way to search of this. I'm not sure of the terminology to ask the question, so I'll just walk through my problem.

从我的测试来看，似乎if语句将在之前退出试图去阵列[10]。我总是这样吗？意思是，如果我有&&在我的if语句中，左侧​​是false，是否会在测试第二个之前退出？就此而言，它是否总是首先测试左边？

From my tests, it seems the if statement will quit before attempting to go to go to array[10]. I that always the case? Meaning, if I have an && in my if statement and the left side is false, will it always exit before testing the second? And for that matter, will it always test the left first?

public static void main(String[] args) {
        boolean [] array = new boolean [10];
        Arrays.fill(array, true);
        int i = 10;
        if(i < array.length && array[i]){
            System.out.println("WhoHoo!");
        }
}

推荐答案

来自关于运营商的 Java教程：

&&和||运算符对两个布尔表达式执行Conditional-AND和Conditional-OR
操作。这些运算符表现出
短路行为，这意味着只有在需要时才会计算第二个操作数
。

The && and || operators perform Conditional-AND and Conditional-OR operations on two boolean expressions. These operators exhibit "short-circuiting" behavior, which means that the second operand is evaluated only if needed.

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