1.Scamner 获得一组数据的最大值和平均值

public static void main(String[] args){
    Scanner scanner = new Scanner(System.in);
    double sum = 0;
    int m = 0;
    while (scanner.hasNextDouble()){
        double x = scanner.nextDouble();
        sum = sum + x;
        m++;

    }
    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();

}

2.实现if多选择结构的持续输入(反馈成绩合格与否)

package com;

import java.util.Scanner;

public class Test {
    public static void main(String[] args) {
        Scanner scanner = new Scanner(System.in);
        while (true){
            int s = scanner.nextInt();
            if (s>=60&s<=100){
                System.out.println("成绩合格");
            }else if(s>=0&s<60){
                System.out.println("成绩不合格");
            }else{
                System.out.println("成绩不合法");
            }
        }

    }
    
}


3.Switch选择结构(匹配后输出不同结果)  (记得加上break,避免case穿透现象)

package com;

public class Test {
    public static void main(String[] args) {
        char grade = 'A';
        switch (grade){
            case 'A':
                System.out.println("优秀");
                break;
            case 'B':
                System.out.println("良好");
                break;
            case 'C':
                System.out.println("及格");
                break;
            case 'D':
                System.out.println("还需努力");
                break;
            default:
                System.out.println("输入错误,无法匹配");
        }

    }

}

4.While循环 (计算1+2+3+...+100=?)

package com;

public class Test {
    public static void main(String[] args) {
       int i =1;
       int sum = 0;
       while (i<=100){
           sum += i;
           i++;

       }
        System.out.println(sum);

    }

}
注意:i++的位置,位于sum += i;上方则整体大100



5.do while循环和while循环区别之 do while至少执行一次 (多次执行结果相同)





6.For循环(分别计算0到100奇数的和与偶数的和)

package com;

public class Test {
    public static void main(String[] args) {
       int oddSum = 0 ;
       int evenSum = 0 ;

        for (int i = 0; i <= 100; i++) {
            if (i%2==0){
                evenSum += i;
            }else {
                oddSum += i;
            }
        }
        System.out.println(oddSum);
        System.out.println(evenSum);
        
    }

}

7.for循环输出1-1000之间能被5整除的数,并且每行输出3个

package com;

public class Test {
    public static void main(String[] args) {
        for (int i = 1; i <= 1000; i++) {
            if (i%5==0){
                System.out.print(i+" ");
                if(i%15==0){
                    System.out.println(" ");
                }
            }
        }

    }

}

8.打印九九乘法表

9.增强for循环