Java第六次作业

1.使用for循环计算1-100的和,除了以3结尾的那些数

 

package Homework;

public class H1 {

    /**
     * @param args
     */
    public static void main(String[] args) {
        // TODO Auto-generated method stub
         int sum=0;
         for(int i=1;i<=100;i++){
             if(i%10!=3)
                 sum+=i;
         }
         System.out.println(sum);
    }

}

 

2.使用二重循环输出以下图形

 

   *

  ***

 *****

*******

 

 

*****

****

***

**

*

package Homework;

public class H2 {

    /**
     * @param args
     */
    public static void main(String[] args) {
        // TODO Auto-generated method stub
        for (int i = 1; i <= 4; i++) {
            for (int j = 1; j <= 4 - i; j++) {
                System.out.print(" ");
            }
            for (int k = 1; k <= 2 * i - 1; k++) {
                System.out.print("*");
            }
            System.out.println();
        }
        System.out.println();
        System.out.println();
        System.out.println();
        System.out.println();
        for (int i = 1; i <= 5; i++) {
            for (int j = 1; j <= 6 - i; j++) {
                System.out.print("*");
            }
            System.out.println();
        }
    }

}

3.循环输入学生姓名,直到输入Q’程序结束

 

package Homework;
import java.util.Scanner;
public class H3 {

    /**
     * @param args
     */
    public static void main(String[] args) {
        // TODO Auto-generated method stub
        Scanner input = new Scanner(System.in);
        while (true) {
            System.out.println("输入学生姓名");
            String a = input.next();
            if (a.equals("Q")) {
                System.out.println("输入的名字有效");
                break;
            } else
                System.out.println("输入的名字无效,请重新输入");

        }
    
    }

}

 

4.输入5个学生成绩,求和,当输入不合法的时候,提示输入错误重新输入。

 

package Homework;
import java.util.Scanner;
public class H4 {

    /**
     * @param args
     */
    public static void main(String[] args) {
        // TODO Auto-generated method stub
        Scanner input = new Scanner(System.in);
        System.out.println("输入学生成绩");
        int sum = 0;
        for (int i = 1; i <= 5; i++) {
            int grade = input.nextInt();
            while (grade < 0 || grade > 100) {
                System.out.println("输入的成绩无效,重新输入");
                grade = input.nextInt();
                break;
            }
            sum += grade;
        }
        System.out.println(sum);
    }

}

 

5.计算 1+ 1/(1+2)+  1/(1+2+3)+  1/(1+2+3+4) +…………+1/(1+2+....+10)

 

package Homework;

public class H5 {

    /**
     * @param args
     */
    public static void main(String[] args) {
        // TODO Auto-generated method stub
         double sum = 0;
            double j = 0;
            for (int i = 1; i <= 10; i++) {
                sum += i;
                j = 1 / sum + j;
            }
            System.out.println(j);
    }

}

 

作业

1.产生一个1-99的随机数,猜数字,若大了就提示“大了点”,若小了就提示“小了点”直到猜对位置

package Homework;

import java.util.Scanner;

public class H6 {

    /**
     * @param args
     */
    public static void main(String[] args) {
        // TODO Auto-generated method stub
         Scanner input = new Scanner(System.in);
            int number = (int) (Math.random() * 100);
            System.out.println("我这里有一个0到99之间的整数,你猜是多少?");
            int a = 0;
            do {
                int b = input.nextInt();
                if (b < number) {
                    System.out.println("小了点!");
                    a++;
                } else if (b > number) {
                    System.out.println("大了点!");
                    a++;
                } else {
                    System.out.println("猜对啦!");
                    a++;
                    break;
                }
            } while (true);
            System.out.println("这个数字是" + number);
            System.out.println("您猜的次数是" + a);
            if (a >= 1 && a <= 3) {
                System.out.println("太棒了!");
            } else if (a >= 5 && a <= 8) {
                System.out.println("一般般!");
            } else {
                System.out.println("太笨了!");
            }
    }
}

2.输入一个数,判断是不是质数(只能被1和自身整除的数是质数)

package Homework;
import java.util.Scanner;
public class H7 {

    /**
     * @param args
     */
    public static void main(String[] args) {
        // TODO Auto-generated method stub
        Scanner input = new Scanner(System.in);
        System.out.println("输入一个数");
        int num = input.nextInt();
        boolean isPrime = true;
        if (num == 1) {
            isPrime = false;
        }
        for (int i = 2; i <= num - 1; i++) {
            if (num % i == 0) {
                isPrime = false;
                break;
            }
        }

        if (isPrime) {
            System.out.println(num + "是质数");
        } else {
            System.out.println(num + "不是质数");
        }
    }

}

3.求裴波那契数列的第20项是什么。裴波那契数列,1,1,2,3,5,8,13,21……\

package Homework;

public class H9 {

    /**
     * @param args
     */
    public static void main(String[] args) {
        // TODO Auto-generated method stub
        int a=1,b=1,c=0;
        for(int i=1;i<=18;i++){
            c=a+b;
            a=b;
            b=c;
            System.out.println(c);
        }
        System.out.println("所以这个数列第20项是:"+c);
    }

}

 

 

 

posted @ 2021-04-09 16:37  曲蔓特  阅读(43)  评论(0编辑  收藏  举报