java第五次作业

1.分别使用for循环，while循环，do循环求1到100之间所有能被3整除的整数的和。

package School.Day6;

public class Test03 {
    public static void main(String[] args){
        int i = 1;
        int sum = 0;
        for( i = 1;i<=100;i++){
            if(i%3 == 0){
                sum = sum + i;
            }
        }
        System.out.println(sum);
        i = 1;
        sum = 0;
        while(i<=100){
            if(i%3 == 0){
                sum = sum + i;
            }
            i++;
        }
        System.out.println(sum);
        sum = 0;
        i = 1;
        do{
            if(i % 3 == 0){
                sum = sum + i;
            }
            i++;
        }while(i<=100);
        System.out.println(sum);
    }
}

　　

2.输出0-9之间的数，但是不包括5。

package School.Day6;

public class Test04 {
    public static void main(String[] args) {
        for (int i = 0; i <= 9; i++) {
            if (i != 5 ) {
                System.out.println(i);
            }
        }
    }
}

　　

3.编写一个程序，求整数n的阶乘

package School.Day6;

import java.util.Scanner;

public class Test05 {
    public static void main(String[] args) {
        System.out.print("输入一个数: ");
        Scanner s = new Scanner(System.in);
        int x = s.nextInt();
        int sum = 1;
        for (int i = x; i > 0; i--) {
            sum = sum * i;
        }
        System.out.println(x + "的阶乘是" +sum);
    }
}

　　

4.编写一个程序，输入任意学生成绩,如果输入不合法(<0或者>100),提示输入错误,重新输入,直到输入合法程序结束

package School.Day6;

import java.util.Scanner;

public class Test06 {
    public static void main(String[] args){
        Scanner s = new Scanner(System.in);
        System.out.print("输入成绩: ");
        double x = s.nextDouble();
        while(true){
            if(x>0 && x<100){
                System.out.println("输入成功!");
                return;
            }else{
                System.out.println("成绩不合法");
                System.out.print("输入成绩: ");
                x = s.nextDouble();
            }
        }
    }
}

　　

5．假设某员工今年的年薪是30000元，年薪的年增长率6%。编写一个Java应用程序计算该员工10年后的年薪，并统计未来10年（从今年算起）总收入。

package School.Day6;

public class Test07 {
        public static void main(String[] args){
            double gongzi = 30000.00;
            double heji = 0;
            for(int i = 1 ;i<=9;i++){
                gongzi = gongzi + (gongzi * 0.06);
                heji = heji + gongzi;
            }
　　　　　　　heji = heji + 30000;
            System.out.println("十年后工资是: " + gongzi);
            System.out.println("这十年工资合计是: " + heji);
        }
}

　　

1.打印出所有的"水仙花数"

package School.Day6;

public class Test02 {
    public static void main(String[] args) {
        for (int i = 100; i < 1000; i++) {
            int a = i/100;
            int b = i%100/10;
            int c = i%10;
            int a3 = a * a * a;
            int b3 = b * b * b;
            int c3 = c * c * c;
            if (a3 + b3 + c3 ==i) {
                System.out.println("水仙花: " + i);
            }
        }
    }
}

　　

2.输入年月日，判断这是这一年中的第几天

package School.Day6;
import java.util.Scanner;
public class Test01 {
    public static void main(String[] args) {
        Scanner s = new Scanner(System.in);
        System.out.print("输入年份: ");
        int y  = s.nextInt();
        System.out.print("输入月份: ");
        int m  = s.nextInt();
        System.out.print("输入日: ");
        int d = s.nextInt();
        int tianshu = 0;
        switch(m){
            case 12:
                tianshu = tianshu + 30;
            case 11:
                tianshu = tianshu + 31;
            case 10:
                tianshu = tianshu + 30;
            case 9 :
                tianshu = tianshu + 31;
            case 8 :
                tianshu = tianshu + 31;
            case 7 :
                tianshu = tianshu + 30;
            case 6 :
                tianshu = tianshu + 31;
            case 5 :
                tianshu = tianshu + 30;
            case 4 :
                tianshu = tianshu + 31;
            case 3 :
                if (y%4==0 && y%100 !=0 || y%400 ==0) {
                    tianshu = tianshu + 29;
                }else{
                    tianshu = tianshu + 28;
                }
            case 2:
                if (y%4==0 && y%100 !=0 || y%400 ==0) {
                    if (d > 29 && m == 2) {
                        System.out.println("2月最多29天!");
                        return;
                    }
                }else{
                    if (d > 28 && m ==2) {
                        System.out.println("平年2月只有28天!");
                        return;
                    }
                }
                tianshu = tianshu + 31;
            default:
                break;
        }
        tianshu = tianshu + d;
        System.out.println(y + "年" + m + "月" + d + "日是这一年的第" + tianshu +"天");
    }
}

　　

3.由控制台输入一个4位整数，求将该数反转以后的数

package School.Day6;

import java.util.Scanner;

public class Test08 {
    public static void main(String[] args) {
        Scanner c = new Scanner(System.in);
        System.out.print("输入四位数: ");
        int a = c.nextInt();
        if (a > 9999 || a < 1000 ) {
            System.out.println("数字错误!");
            System.exit(0);
        }
        int s = a / 1000;
        int h = a % 1000 /100;
        int m = a % 100 /10;
        int g = a % 10;
        System.out.print(a + "的反转数为: " );
        System.out.print(g);
        System.out.print(m);
        System.out.print(h);
        System.out.print(s);
    }
}