3.输出，输入，基本数据类型

Posted 2020-08-26 894316728

1.输出

package com.example;

public class MyClass {
    public  static void main(String args[]){
        System.out.println(Byte.MIN_VALUE + "~" + Byte.MAX_VALUE);

        System.out.println(Integer.parseInt("1000"));
        System.out.println(Integer.toBinaryString(100));
        System.out.println(Integer.toHexString(100));
        System.out.println(Integer.toString(200));
    }
}

 2.输入

package com.example;

import java.util.Scanner;

public class MyClass {
    public static void main(String[] args){
        //scanner从控制台输入数据
        Scanner scanner = new Scanner(System.in);

        System.out.println("姓名：");
        String name = scanner.next();

        System.out.println("性别：");
        char sex = scanner.next().charAt(0);

        System.out.println("年龄：");
        int age = scanner.nextInt();

        System.out.println("身高");
        double height = scanner.nextDouble();

        System.out.print("性格");
        String type = scanner.next();

        System.out.println("嗨，大家好，我是："+name+"，性别："+sex+",年龄："+age+"，身高："+height+",性格："+type);
小雨，女，22，1.62，哈哈

       
    }
}

 3.基本数据类型及其转换

package com.example;

public class MyClass {
    public  static  void  main(String[] args){
        //1.
        long longValue = 3000000000l;
        //2.
        //自动转：byte->short->int->long
        //强转：long->ing->short->byte
        //3.
        byte b1 = 5;
        //因为一个整形数在内部存储为int
        //所以 byte b3 = b1 + 3是错的，可改成以下两种形式：
        byte b2 = (byte)(b1 + 3);
        int b3 = b1 + 3;


        //1.
        float c = 4.3f;
        //2.
        //自动转：float->double
        //强转：double->float

        //char类型：字符，汉字，英文字母，由‘‘阔起来

        //BOOL类型：TRUE和FALSE
    }
}