boolean 关键字

概述

boolean 关键字用于声明布尔类型变量,只有两个值:truefalse

特性

  • 取值:true 或 false
  • 默认值:false

基本用法

public class BooleanExample {
    public static void main(String[] args) {
        // 声明和初始化
        boolean isActive = true;
        boolean isComplete = false;
        boolean hasPermission;

        // 逻辑运算
        boolean result1 = true && false;  // false
        boolean result2 = true || false;  // true
        boolean result3 = !true;          // false

        // 比较运算
        int a = 5, b = 10;
        boolean isEqual = (a == b);       // false
        boolean isGreater = (a > b);      // false
        boolean isLessEqual = (a <= b);   // true

        // 条件判断
        if (isActive) {
            System.out.println("处于活动状态");
        }

        if (!isComplete) {
            System.out.println("尚未完成");
        }
    }
}

方法返回值

public class BooleanMethods {
    public boolean isEven(int number) {
        return number % 2 == 0;
    }

    public boolean isValidAge(int age) {
        return age >= 0 && age <= 150;
    }

    public boolean isEmpty(String str) {
        return str == null || str.length() == 0;
    }

    public static void main(String[] args) {
        BooleanMethods bm = new BooleanMethods();

        System.out.println("4是偶数:" + bm.isEven(4));
        System.out.println("25是有效年龄:" + bm.isValidAge(25));
        System.out.println("空字符串:" + bm.isEmpty(""));
    }
}

boolean类型是控制程序逻辑流程的基础,常用于条件判断和标志位。

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