Java基本数据类型及变量类型

package com.leo.demo;

/**
 * @author
 */
public class MainClass {
    static boolean bo;
    static byte by;
    static short sh;
    static int i;
    static long l;
    static float f;
    static double d;
    static char c;
    static String st;

    public static void main(String[] args) {
        // Byte 默认值0
       System.out.println(Byte.SIZE);
       System.out.println(Byte.MIN_VALUE);
       System.out.println(Byte.MAX_VALUE);
       System.out.println("byte default value：" + by);

       // Short 默认值0
       System.out.println(Short.SIZE);
       System.out.println(Short.MIN_VALUE);
       System.out.println(Short.MAX_VALUE);
       System.out.println("Short default value：" + sh);

       // Int 默认值0
       System.out.println(Integer.SIZE);
       System.out.println(Integer.MIN_VALUE);
       System.out.println(Integer.MAX_VALUE);
       System.out.println("Int default value：" + i);

       // Long 默认值0L
       System.out.println(Long.SIZE);
       System.out.println(Long.MIN_VALUE);
       System.out.println(Long.MAX_VALUE);
       System.out.println("Long default value：" + l);

       // Float 默认值0.0f
       System.out.println(Float.SIZE);
       System.out.println(Float.MIN_VALUE);
       System.out.println(Float.MAX_VALUE);
       System.out.println("Float default value：" + f);

       // Double 默认值0.0d
       System.out.println(Double.SIZE);
       System.out.println(Double.MIN_VALUE);
       System.out.println(Double.MAX_VALUE);
       System.out.println("Double default value：" + d);

       // Char 默认值'u000'
       System.out.println(Character.SIZE);
       System.out.println((int) Character.MIN_VALUE);
       System.out.println((int)Character.MAX_VALUE);
       System.out.println("Char default value：" + c);

       // String
       System.out.println("String default value：" + st);

       // 常量使用final关键字声明
       final double PI = 3.1415926;
       System.out.println(PI);
    }
}

package com.leo.demo;

/**
 * @author leo
 */
public class MainClass {

    public static void main(String[] args) {
        Coder coder1 = new Coder("java");
        coder1.getAge();
        coder1.setSalary(10000.0);
        coder1.getCoderInfo();
    }
}

class Coder {
    /**实例变量，对子类可见**/
    public String name;
    /**私有变量，在该类可见**/
    protected double salary;
    /**静态私有变量**/
    private static double score;
    /**常量**/
    private static final String department = "development";
    public Coder(String coderName) {
        name = coderName;
    }
    public void getAge() {
        // 局部变量
        int age = 0;
        age = age + 35;
        System.out.println("年龄：" + age);
    }

    public void setSalary(double coderSalary) {
        salary = coderSalary;
    }

    public void getCoderInfo() {
        System.out.println("名字：" + name);
        System.out.println("薪水：" + salary);
        System.out.println("部门：" + department);
        score = 99.2;
        System.out.println("绩效分：" + score);
    }
}