第三次上机

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 huaerzi;
import java.util.Scanner;
public class huada {
    public static void main(String[] args) {
          // TODO Auto-generated method stub
        for(int n=100;n<=999;n++){
            int Bai=n/100;               
            int Shi=(n%100)/10;         
            int Ge=n%10;                   
            if((Bai*Bai*Bai)+(Shi*Shi*Shi)+(Ge*Ge*Ge)==n)  
            {
 
                System.out.println(n);
            }                     
        }    
    }   
}

2.在控制台输出以下图形（知识点：循环语句、条件语句）

package huaerzi;
public class huada {
    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();
                }
            }

            }

package huaerzi;
public class huada {
    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();
        }
    }
}
    

package huaerzi;
public class huada {
    public static void main(String[] args) {
         for(int i=1;i<=6;i++) {
                for(int j=i;j>0;j--) {
                    System.out.print(j);
                }
                System.out.println();
            }
        }
    }

package huaerzi;
public class huada {
    public static void main(String[] args) {
          for(int i=6;i>0;i--) {
                for(int k=0;k<6-i;k++) {
                    System.out.print(" ");
                }
                for(int j=1;j<=i;j++) {
                    System.out.print(j);
                }
                System.out.println("");
            }
        }
    }

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）

package huaerzi;
import java.util.Scanner;
public class huada {
    public static void main(String[] args) {
          // TODO Auto-generated method stub
        int year;    
        int mouth;    
        int day = 0;
        int days;    
        int x = 0;    
        int e = 0;    
        Scanner scanner = new Scanner(System.in);                
        do {
            System.out.println("请输入年:");    
            year = scanner.nextInt();    
            System.out.println("请输入月:");        
            mouth = scanner.nextInt();    
            System.out.println("请输入日:");
            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;}    
            x += day;}    
              System.out.println("第" + year + "年的第" + (x+ days) + "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 huaerzi;
import java.util.Scanner;
public class huada {
    public static void main(String[] args) {
          // TODO Auto-generated method stub
         Scanner sc = new Scanner(System.in);
           int x = sc.nextInt();
           if(x>999 && x<=9999){
               int ge = x%10;
               int shi = x % 100 / 10;
               int bai = x%1000/100;
               int qian = x/1000;
               int sum = qian + bai*10 +shi*100 +ge*1000;
               System.out.println(sum);
           }         
    }
}