类和对象:
类和对象是面向对象编程(oops)的基本概念,用于表示现实世界的概念和实体。[]
类代表一组具有相似属性和行为的对象。
例如:
动物型狗:
DOG - 是一个类,而名为 TOMMY 的特定狗是狗的对象。
班级:
java中的类是一组具有共同特征/行为和共同属性/属性的对象。
它是一个用户定义的蓝图原型,从中创建对象。
类在创建时不会分配内存。
类是使用 class 关键字声明的
员工类{}
这里定义类的唯一方法是使用 class 关键字。
例如:
STUDENT 是一个类,而名为 RAVI 的特定学生是一个对象。
对象:
对象被认为是一个物理实体,它代表一个类。
对象代表现实生活中的实体和类的内存引用。
对象是类的实例,它们被创建来使用类的属性和方法。java 程序创建许多对象。
一个对象由状态、行为和身份组成。
创建对象:
对象是通过 new 关键字创建的。
员工 ob=新员工();
1.如何用Java创建对象
The object is a basic building block of an object oriented language(oops). In Java, we cannot execute any program without creating an object. There is various way to create an object in Java that we will discuss in this section, and also learn how to create an object in Java.
Java 提供了五种创建对象的方法。
Using new Keyword Using clone() method Using new Instance() method of the Class class Using new Instance() method of the Constructor class Using deserialization
2.java中如何调用方法:
A method in Java is a group of statements that carry out a certain action or function. It is commonly used because it enables code reuse, which refers to the ability to write code once and use it multiple times.
要在 Java 中调用方法,您需要遵循以下基本步骤:
Define the method: This includes giving the method a name, specifying any arguments that it takes, and defining what the method should do when it is called. Create an instance of the class: If the method you want to call is part of a class, you need to create an instance of that class. Call the method: Once you have an instance of the class (if necessary), you can use the name of the method, followed by any arguments that the method takes (if any) to call the method.
java中方法是如何定义的:
To define a method in Java, you need to declare it within a class. The following elements in the method declaration:
Return type: The data type of the value the method returns, or void if it doesn't return a value Method name: The name of the method Parentheses: A pair of parentheses, () Method body: The code for the method, enclosed in braces, {}
可以包含在方法声明中的其他元素有:
Modifiers: Such as public or private Parameter list: A comma-delimited list of input parameters, preceded by their data types Exception list: An exception list
程序任务:
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