第五周作业

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）

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package xx;

public class pika {

    public static void main(String[] args) {
        int g,s,b,sum=0;
        for(int i = 100;i<=999;i++) {
            g=i%10;
            s=i/10%10;
            b=i/100;
            sum=g*g*g+s*s*s+b*b*b;
            if(sum==i) {
                System.out.print(i+" ");
            }
        }
    }
}
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 2.在控制台输出以下图形（知识点：循环语句、条件语句）

 

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package xx;

import java.util.Scanner;

public class pika {

    public static void main(String[] args) {
        for(int i = 1; i <= 6; i++) {
            for(int j = 1; j <= i; j++) {
            System.out.print(j+" ");
        }
        System.out.println();
        }
    }
}
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package xx;

import java.util.Scanner;

public class pika {

    public static void main(String[] args) {
        for(int i = 1; i <= 6; i++) {
            for(int j = 1; j <= 7-i; j++) {
            System.out.print(j+" ");
        }
        System.out.println();
        }
    }
}
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package xx;

import java.util.Scanner;

public class pika {

    public static void main(String[] args) {
        for(int i = 1; i <= 6; i++) {
            for(int j = i; j >= 1; j--) {
            System.out.print(j+" ");
        }
        System.out.println();
        }
    }
}
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package xx;

public class pika {

    public static void main(String[] args) {
        for (int a = 6; a >= 1; a--) {
            for (int i = 1; i <= 7 - a; i++) {
                System.out.print(" ");
            }
            for (int j = 1; j <= a; j++) {
                System.out.print(j);
            } 
            System.out.println(" ");
        }
    }
}
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 3. 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)

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package li;

import java.util.Scanner;

public class Test05{

    public static void main(String[] args) {
        int year;
        int mouth;
        int day = 0;
        int days;
        int d = 0; // 累计天数
        int e = 0;
        Scanner scanner = new Scanner(System.in);
        
        //判断输入的年份和月份和日期是否错误
        do {
            System.out.println("输入年:");
            year = scanner.nextInt();
            System.out.println("输入月:");
            mouth = scanner.nextInt();
            System.out.println("输入日:");
            days = scanner.nextInt();
            if (year < 0 || mouth < 0 || mouth > 12 || days < 0 || days > 31) {
                System.out.println("input error!");
                e = 1;
            }
        } while (e == 1);
        
        for (int i = 1; i < mouth; i++) {
            switch (i) {
            case 1:
            case 3:
            case 5:
            case 7:
            case 8:
            case 10:
            case 12: {
                day = 31;
                break;
            }
            case 4:
            case 6:
            case 9:
            case 11: {
                day = 30;
                break;
            }
            case 2: {
                if ((year % 100 != 0 && year % 4 == 0) || (year % 100 == 0 && year % 400 == 0)) {
                    day = 29;
                } else {
                    day = 28;
                }
            }
            default:
                break;
            }
            d += day;
        }
        System.out.println("这是" + year + "年的" + (d + days) + "天");
    }
}
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4.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
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package li;

import java.util.Scanner;

public class Test05 {
public static void main(String[] args) {
int a, b, c, d, e, x;

Scanner sc = new Scanner(System.in);
System.out.println("输入数字：");
e = sc.nextInt();

a = e / 1000;
b = e / 100 % 10;
c = e / 10 % 10;
d = e % 10;
x = d * 1000 + c * 100 + b * 10 + a;

System.out.println("反转后数为：" + x);
 }

}
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posted @ 2020-04-02 11:53  清欢渡￥  阅读(112)  评论(0)    收藏  举报