JAVA第五周作业0402

package com.homwork5;
//1~100之间所有能被3整除的数的和  for  while  do
public class Test5_1_1 {
    public static void main(String[] args) {
        int sum1 = 0;
        for (int i = 1; i <= 100; i++) {
            if (i % 3 == 0) {
                sum1 += i;
            }
        }
        System.out.println(sum1);//for
        int j = 1;
        int sum2 = 0;
        while (j<=100) {
            if (j % 3 == 0) {
                sum2 += j;
            }
            j ++;
        }
        System.out.println(sum2);//while        
        int k = 1;
        int sum3 = 0;
        do {
            if (k % 3 == 0) {
                sum3 += k;
            }
            k ++;
        } while (k<100);
        System.out.println(sum3);
        }
}

 

 

 

package com.homwork5;

public class Test5_1_2 {
//输出0~9之间的数，不包括5
    public static void main(String[] args) {
        for (int i = 0; i < 10; i++) {
            if (i!=5) {
                System.out.println(i);
            }
        }

    }

}

 

 

 

package com.homwork5;

import java.util.Scanner;

//求整数n的阶乘
public class Test5_1_3 {
    public static void main(String[] args) {
        Scanner input = new Scanner(System.in);
        System.out.println("请输入一个整数");
        int n = input.nextInt();
        int result = 1;
        for (int i = 1; i <= n; i++) {
            result *= i;
        }
        System.out.println(n + "!="+result);
    }
}

 

 

 

package com.homwork5;

import java.util.Scanner;

public class Test5_1_4 {
    public static void main(String[] args) {
        Scanner input = new Scanner(System.in);
            System.out.println("请输入学生成绩:");
            int grade = input.nextInt();
            for (; grade < 0 || grade > 100; ) {
                System.out.println("输入不合法!\n请重新输入0~100!");
                grade = input.nextInt();
            }
            System.out.println(grade);
    }
}

 

 

 

package com.homwork5;

public class Test5_1_5 {
    public static void main(String[] args) {
        double first = 30000;
        double sum =first;
        for (int i = 1; i <= 10; i++) {
            first *= 1.06;
            sum += first;
        }
        System.out.println("十年后的工资是" + first);
        System.out.println("十年后的总工资是" + sum);
    }
}

 

 

 

package com.homwork5;

public class Test5_2_1 {

    /**
     * 打印出所有的"水仙花数"，所谓"水仙花数"是指一个三位数，
     * 其各位数字立方和等于该数本身。例如：153是一个"水仙花数"，
     * 因为153=1的三次方＋5的三次方＋3的三次方。（知识点：循环语句、条件语句）
     */
    public static void main(String[] args) {
        for (int i = 100; i <= 999; i++) {
            int ge = i %10;
            int shi = i %100/10;
            int bai = i %1000/100;
            if (ge*ge*ge+shi*shi*shi+bai*bai*bai==i) {
                System.out.println(i);
            }
        }

    }

}

 

 

 

package com.homwork5;

import java.util.Scanner;

//输入年月日，判断这是这一年中的第几天（知识点：循环语句、条件语句）
public class Test5_2_2 {
    public static void main(String[] args) {
        Scanner input = new Scanner(System.in);
        System.out.println("请输入年");
        int year = input.nextInt();
        System.out.println("请输入月");
        int month = input.nextInt();
        System.out.println("请输入日");
        int day= input.nextInt();
        int sum = 0;
        
        switch (month-1) {
        case 12:sum +=31;
        case 11:sum +=30;
        case 10:sum +=31;
        case 9:sum +=30;
        case 8:sum +=31;
        case 7:sum +=31;
        case 6:sum +=30;
        case 5:sum +=31;
        case 4:sum +=30;
        case 3:sum +=31;
        case 2:
            if (year%4==0&&year%100!=0||year%400==0) {
                sum += 29;
            }else{
                sum += 28;
            }
        case 1:sum +=31;
        default:
            break;
        }
        sum +=day;
        System.out.println("这是这一年中的第" + sum + "天!");
    }
}

 

 

 

package com.homwork5;

import java.util.Scanner;

public class Test5_2_3 {
/*    由控制台输入一个4位整数，求将该数反转以后的数，如原数为1234，
    反转后的数位4321 */

    public static void main(String[] args) {
        Scanner input = new Scanner(System.in);
        System.out.println("请输入一个四位数的整数:");
        int num = input.nextInt();
        for (; 9999 < num || num < 1000 ;) {
            System.out.println("输入不合法!\n请重新输入一个四位数的整数");
            num = input.nextInt();
        }
        int ge = num %10 *1000;
        int shi = num %100 /10 *100;
        int bai = num %1000 /100 *10;
        int qian = num %10000 /1000;
        int sum = ge +shi +bai +qian;
        System.out.println(sum);
        

    }

}