Item 57: Minimize the scope of local variables 与旧式的C语言不同,Java允许在任何地方进行变量声明。 最有效的方式是:在第一次使用前进行变量声明(方便控制变量周期) 几乎所有的变量声明都应该进行初始化。例外是当变量初始化可能抛出异常时,在try-catch语句中进行初始化。 循环中的变量声明。使用for循环方式优先...
to store the limit of the first, thus avoiding the cost of a redundant computation on every iteration. Keep methods small and focused . If you combine two activities in the same method, local variables relevant to one activity may be in the scope of the code performing the other activity. ...
局部变量的初始化是强制性的。 The scope of these variables exists only within the block in which the variable is declared. i.e. we canaccessthese variableonly within that block. 不能使用“静态”关键字定义局部变量,因为static定义的变量属于类,所以static只能在方法的外面类的里面声明。 局部变量如果使...
Thescopeof a variable refers to the parts of a class within which the variable exists and can be used. The basic rule is that a variable exists only within the block in which it is declared. (In Java, ablockis defined by a matching set of braces.) ...
10.5.6 Polymorphic Processing, Operator instanceof and Downcasting 10.6 Allowed Assignments Between Superclass and Subclass Variables 10.7 final Methods and Classes 10.8 A Deeper Explanation of Issues with Calling Methods from Constructors 10.9 Creating and Using Interfaces 10.9.1 Developing a ...
6．11 Scope of Declarations 182 6．12 Method Overloading 184 6．13 (Optional) GUI and Graphics Case Study： Colors and Filled Shapes 186 6．14 Wrap-Up 188 Chapter 7 Arrays and ArrayLists 201 7．1 Introduction 202 7．2 Arrays 202 7．3 Declaring and Creating Arrays 203 7．4 Examp...
In the Java programming language, the terms "field" and "variable" are both used; this is a common source of confusion among new developers, since both often seem to refer to the same thing. The Java programming language defines the following kinds of variables: Instance Variables (Non-...
Item 45: Minimize the scope of local variables 209 Item 46: Prefer for-each loops to traditional for loops 212 Item 47: Know and use the libraries 215 Item 48: Avoid float and double if exact answers are required 218 Item 49: Prefer primitive types to boxed primitives 221 Item 50: ...
Scope of pattern variablesCopy heading link Pattern variables are local variables, which are casted and initialized when a type pattern tests true. Their scope is limited to the case labels in which they are declared – it doesn’t make sense for a pattern variable to be available in a switc...