Java第五次上机作业

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）

package com.a01;

import java.util.*;

public class hellowold {
    public static void main(String[] args) {
        System.out.println("输入一个三位数");
        Scanner input = new Scanner(System.in);
        int n = input.nextInt();
        int ge, shi, bai, i;
        for (i = 100; i <= 999; i++) {
            if (n >= 100 && n <= 999) {
                ge = n % 100 % 10;
                shi = n % 100 / 10;
                bai = n / 100;

                System.out.println("个位，十位，百位的立方和为：" + (ge * ge * ge + shi * shi * shi + bai * bai * bai));
                break;
            }
            System.out.println("输入不合法，请重新输入");
            n = input.nextInt();
        }

    }
}

 

 

 

2.

在控制台输出以下图形（知识点：循环语句、条件语句）

 

package com.a01;

public class hellowold {
    public static void main(String[] args) {
        int a, b;
        for (a = 1; a <= 6; a++) {
            for (b = 1; b <= a; b++) {
                System.out.print(b);
            }
            System.out.println("\n");
        }

    }
}

 

 

package com.a01;

public class hellowold {
    public static void main(String[] args) {
        int a, b;
        for (a = 6; a >= 1; a--) {
            for (b = 1; b <= a; b++) {
                System.out.print(b);
            }
            System.out.println("\n");
        }

    }
}

 

 

 

 

package com.a01;

public class hellowold {
    public static void main(String[] args) {
        int a, b;
        for (a = 1; a < 7; a++) {
            for (b = 7; b > 0; b--) {
                if (b <= a) {
                    System.out.print(b);
                } else {
                    System.out.print(" ");
                }

            }
            System.out.println("\n");
        }

    }
}

 

 

 

 

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）

import java.util.*;

public class hellowold {
    public static void main(String[] args) {

        Scanner input = new Scanner(System.in);
        System.out.println("year");
        int year = input.nextInt();
        System.out.println("mouth");
        int month = input.nextInt();
        System.out.println("day");
        int day = input.nextInt();
        int total = 0;
        for (int i = 1; i < month; i++) {

            switch (i) {
            case 4:
            case 6:
            case 9:
            case 11:
                total += 30;
                break;
            case 2:
                if (year % 4 == 0 && year % 100 != 0 || year % 400 == 0)

                    total += 29;
                else
                    total += 28;
                break;
            default:
                total += 31;
                break;
            }

        }
        total += day;
        System.out.println("该天是第" + total + "天");

    }
}

 

 

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（知识点：循环语句、条件语句）

package com.a01;

import java.util.*;

public class hellowold {
    public static void main(String[] args) {

        Scanner input = new Scanner(System.in);
        System.out.println("输入一个四位数");
        int n = input.nextInt();
        int a,b,c,d,i,t,k;
        a:for(i=1000;i<=9999;i++){
            
                a=n%100%10;
                b=n%100/10;
                c=n%1000/100;
                d=n/1000;
                t=a;
                a=d;
                d=t;
                k=b;
                b=c;
                c=k;
                System.out.println("转化为："+d+c+b+a);
                break a;
            
        }
        
        
    }
}