Scanner进阶使用

package com.yue.scanner;

import java.util.Scanner;

public class Demo04 {
    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：");

        //如果...那么
        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！");
        }

        System.out.println("请输入小数：");

        //如果...那么
        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！");
        }


        scanner.close();
    }
}

package com.yue.scanner;

import java.util.Scanner;

public class Demo05 {
    public static void main(String[] args) {

        Scanner scanner = new Scanner(System.in);

        //和
        double sum = 0;
        //计算输入了多少个数字
        int m = 0;

        //通过循环判断是否还有输入，并在里面对每一次进行求和统计
        while (scanner.hasNextDouble()){
            double x = scanner.nextInt();
            m =m+1;
            sum=sum+x;
            System.out.println("你输入"+m+"个数据,然后当前结果是sum:"+sum);
        }
        System.out.println(m+"个数的和为"+sum);
        System.out.println(m+"个数的平均值是"+(sum/m));




        scanner.close();
    }
}