问题描述

如果你有这样的代码:

if (A > X && B > Y)
{
   Action1();
}
else if(A > X || B > Y)
{
   Action2();
}

使用 A >X 和 B >Y，if-else-if 梯形图的两个部分都会执行吗?

With A > X and B > Y, will both parts of the if-else-if ladder be executed?

我正在处理存在这种情况的 Java 代码.我通常使用 C++ 工作，但我是一个非常新的(和零星的)两种语言的程序员.

I'm dealing with Java code where this is present. I normally work in C++, but am an extremely new (and sporadic) programmer in both languages.

推荐答案

不，它们不会同时执行.它按照您编写它们的顺序排列，从逻辑上讲这是有道理的；即使第二个读作else if"，您仍然可以将其视为else".

No, they won't both execute. It goes in order of how you've written them, and logically this makes sense; Even though the second one reads 'else if', you can still think of it as 'else'.

考虑一个典型的 if/else 块:

Consider a typical if/else block:

if(true){
   // Blah
} else{
   // Blah blah
}

如果您的第一个陈述是正确的，那么您甚至不必费心查看在 else 情况下需要做什么，因为它是无关紧要的.同样，如果你有'if/elseif'，你就不会浪费时间查看后续的块，因为第一个是真的.

If your first statement is true, you don't even bother looking at what needs to be done in the else case, because it is irrelevant. Similarly, if you have 'if/elseif', you won't waste your time looking at succeeding blocks because the first one is true.

一个真实的例子可能是分配成绩.你可以试试这样的:

A real world example could be assigning grades. You might try something like this:

if(grade > 90){
   // Student gets A
} else if(grade > 80){
   // Student gets B
} else if(grade > 70){
   // Student gets c
}

如果学生得到了 99%，那么所有这些条件都是正确的.但是，您不会分配学生 A、B 和 C.

If the student got a 99%, all of these conditions are true. However, you're not going to assign the student A, B and C.

这就是为什么顺序很重要.如果我执行了这段代码，并将 B 块放在 A 块之前，那么您将为同一个学生分配 B 而不是 A，因为不会执行 A 块.

That's why order is important. If I executed this code, and put the B block before the A block, you would assign that same student with a B instead of an A, because the A block wouldn't be executed.