44 lines
2.0 KiB
Markdown
44 lines
2.0 KiB
Markdown
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---
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title: Basic Operations
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localeTitle: 基本操作
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---
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# 基本操作
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Java支持对变量进行以下操作:
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* **算术** : `Addition (+)` , `Subtraction (-)` , `Multiplication (*)` , `Division (/)` , `Modulus (%)` , `Increment (++)` , `Decrement (--)` 。
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* **字符串连接** : `+`可用于字符串连接,但减法`-`在字符串上不是有效操作。
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* **关系** : `Equal to (==)` , `Not Equal to (!=)` , `Greater than (>)` , `Less than (<)` , `Greater than or equal to (>=)` , `Less than or equal to (<=)`
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* **按位** : `Bitwise And (&)` , `Bitwise Or (|)` , `Bitwise XOR (^)` , `Bitwise Compliment (~)` `Zero fill right shift (>>>)` `Bitwise Compliment (~)` , `Left shift (<<)` , `Right Shift (>>)` , `Zero fill right shift (>>>)`
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* **逻辑** : `Logical And (&&)` , `Logical Or (||)` , `Logical Not (!)`
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* **赋值** : `=` , `+=` , `-=` , `*=` , `/=` , `%=` , `<<=` , `>>=` , `&=` , `^=` , `|=`
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* **其他** : `Conditional/Ternary(?:)` , `instanceof`
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虽然大多数操作都是不言自明的,但条件(三元)算子的工作原理如下:
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`expression that results in boolean output ? return this value if true : return this value if false;`
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例: 真实条件:
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```java
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int x = 10;
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int y = (x == 10) ? 5 : 9; // y will equal 5 since the expression x == 10 evaluates to true
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```
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错误条件:
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```java
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int x = 25;
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int y = (x == 10) ? 5 : 9; // y will equal 9 since the expression x == 10 evaluates to false
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```
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运算符的实例用于类型检查。它可用于测试对象是否是类,子类或接口的实例。一般格式 - _类/子类/接口的对象**实例**_
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这是一个程序来说明instanecof运算符: \`\`\`的Java Person obj1 = new Person(); 人obj2 =新男孩();
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```
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// As obj is of type person, it is not an
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// instance of Boy or interface
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System.out.println("obj1 instanceof Person: " + (obj1 instanceof Person)); /*it returns true since obj1 is an instance of person */
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```
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\`\`\`
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