问题描述
当我尝试编译以下Java程序时:
When I attempted to compile the following Java program:
public class MyClass
{
static int f1() { return 10; }
static int f2() { return 20; }
public static void main(String args[])
{
int x = 10;
(x <= 10) ? f1() : f2();
}
}
我得到了错误:
/MyClass.java:9: error: not a statement
(x <= 10) ? f1() : f2();
^
Java语言定义将语句作为赋值,增量/减量,方法之一调用或对象创建。我错误的声明涉及方法调用,因此应该起作用。实际上,如果我只有一条语句:
Java language definition talks about statements as one of assignment, increment/decrement, method invocation or object creation. My erroneous "statement" involves method invocation and should, therefore work. In fact, if I have a single statement like:
f1();
编译器在没有任何抱怨的情况下编译程序。同样,如果我将最后一行更改为:
the compiler compiles the program sans any whimper. Similarly, if I change the final line to:
int y = (x <= 10) ? f1() : f2();
然后,一切都是笨拙的。
then too, everything is hunky-dory.
作为最后的一条信息,C和C ++都不会在以下方面引起人们的注意:
As a final piece of info, neither C nor C++ bats an eyelid on:
(x <= 10) ? f1() : f2();
推荐答案
表达式中使用三元运算符。对于语句,可以使用if语句。这就是语法的定义方式。期间。
The ternary operator is used in expressions. For statements, you can use an if statement. That's how the syntax is defined. Period.
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