Java第一次实训

 package com.wsy.work;
 
 public class JudgeNumber {
 
     public static void main(String[] args) {
         int a = 5;
         if(a % 2 == 0)
         {
             System.out.println(a+"是偶数");
         }
         else
         {
             System.out.println(a+"是奇数");
         }
 
     }
 
 }

 package com.wsy.work;
 import java.math.BigDecimal;
 import java.util.Scanner;
 public class Circle {
 
     public static void main(String[] args) {
         BigDecimal PI  = new BigDecimal("3.14");
         Scanner in = new Scanner(System.in);
         System.out.print("请输入圆的半径:");
         BigDecimal ridius = new BigDecimal(in.nextLine());
         BigDecimal s = ridius.multiply(ridius).multiply(PI);
         System.out.println("圆的面积为："+s);
         in.close();
     }
 
 }

 package com.wsy.work;
 import java.util.Scanner;
 public class EncryptionDevice {
 
     public static void main(String[] args) {
         Scanner in = new Scanner(System.in);
         int number = Integer.parseInt(in.nextLine());
         double result = (number*10+5)/2+3.14159;
         System.out.println("加密结果为:"+result);
     }
 
 }

 package com.wsy.work;
 
 public class Work4 {
 
     public static void main(String[] args) {
         final int CHICKEN = 100;
         final int MONEY = 100;
         for(int i = 0; i<=20; i++)
         {
             for(int j = 0; j<=33; j++)
             {
                 for(int k = 0; k<=300; k=k+3)
                 {
                     if(i*5+j*3+k/3 == MONEY && i+j+k == CHICKEN)
                     {
                         System.out.println("公鸡:"+i);
                         System.out.println("母鸡:"+j);
                         System.out.println("公鸡:"+k);
                         System.out.println("==================================================");
                     }
                 }
 
             }
 
         }
     }
 
 }

 package com.wsy.work;
 
 public class Work5 {
 
     public static void main(String[] args) {
         int number;
         int count = 0;
         for(int i = 1; i<=4; i++)
         {
             for(int j =1; j<=4; j++)
             {
                 for(int k = 1; k<=4; k++)
                 {
                     if(i != j && i != k && j!=k)
                     {
                         count++;
                         number = i*100+j*10+k;
                         System.out.println(number);
                     }
                 }
 
             }
 
         }
         System.out.println("======================================================");
         System.out.println("不重复的数字总共有:"+count+"个");
 
     }
 
 }

 package com.wsy.work;
 import java.util.Scanner;
 public class IsPrime {
 
     public static void main(String[] args) {
         boolean isPrime = true;
         Scanner in = new Scanner(System.in);
         int number = Integer.parseInt(in.nextLine());
         if(number == 1)
         {
             isPrime = false ;
         }
         for(int i = 2; i<=Math.sqrt(number); i++)
         {
             if(number % i ==0)
             {
                 isPrime = false ;
                 break;
             }
         }
         if(isPrime)
         {
             System.out.println(number+"是素数");
         }
         else
         {
             System.out.println(number+"不是素数");
         }
         in.close();
     }
 
 }