JAVA今日2021.8.3

JAVA Scanner

Scanner04

package JAVASE.scanner;

import java.util.Scanner;

public class scanner04 {
    public static void main(String[] args) {
        Scanner scanner = new Scanner(System.in);
        //从键盘接收数据
        int i = 0;
        float f = 0.0f;

        System.out.println("请输入整数：");
        if (scanner.hasNextInt()){
            i = scanner.nextInt();
            System.out.println("整数数据："+ i);
        }else {
            System.out.println("输入的不是整数数据！");
        }
        System.out.println("请输入小数：");
        if (scanner.hasNextFloat()){
            f = scanner.nextFloat();
            System.out.println("小数数据："+ f);
        }else {
            System.out.println("输入的不是小数数据！");
        }



        scanner.close();
    }

}

Scanner05

package JAVASE.scanner;

import java.util.Scanner;

public class scanner05 {
    public static void main(String[] args) {
        //可以输入多个数字，并求其总和与平均数，每输入一个数字用回车确认，通过输入非数字来结束并输出结果。
        Scanner scanner = new Scanner(System.in);
        //和
        double sum = 0;
        //计算输入了多少个数字
        int m = 0;
        System.out.println("请输入数据：");
        //通过循环判断是否还有输入，并进行求和和统计
        while (scanner.hasNextDouble()){
            double x = scanner.nextDouble();
            m = m+1;//m++
            sum = sum +x;
            System.out.println("你输入了第"+m+"个数据，当前结果sum="+sum);
        }
        System.out.println(m +"个数的和为："+sum);
        System.out.println(m +"个数的平均值为："+(sum/m));
        scanner.close();
    }
}

2021.8.3