Java:为什么不能在main之外调用此方法? [英] Java: Why can't I call this method outside of main?

问题描述

作为初学者，我想知道为什么 caller.VelocityC 仅在放入主块时才起作用?

As a beginner I wonder why my caller.VelocityC only works when put inside of the main block?

当我有这样的代码时，我无法调用该方法.

When i have my code like this, I can't call the method.

方法调用类:

public class Velocity2 {

VelocityCounter caller = new VelocityCounter();
caller.VelocityC(6, 3);
}

包含方法的类:

public class VelocityCounter {  
void VelocityC(int s, int v){
    System.out.print(s/v);
  }
}

推荐答案

在Java中，您不能拥有不属于方法一部分的可执行语句. ^* 第一行是可以的:

In Java, you can't have executable statements that aren't part of a method.^* The first line is okay:

VelocityCounter caller = new VelocityCounter();

因为编译器认为您正在声明和初始化类 Velocity2 的名为 caller 的实例变量.但是第二行:

because the compiler thinks you are declaring and initializing an instance variable named caller for class Velocity2. The second line, however:

caller.VelocityC(6, 3);

在类声明的顶层是非法的.

is illegal at the top level of a class declaration.

^* _{从技术上讲，这不太正确.语句也可以出现在构造函数， static 块和实例初始化器块中.}

^*_{Technically, that's not quite right. Statements can also appear in constructors, static blocks, and instance initializer blocks.}

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