实验三——阶乘

 1 import java.util.Scanner;
 2 public class factorial {
 3 
 4     /**
 5      * @param args
 6      */
 7     public static void main(String[] args) {
 8         // TODO Auto-generated method stub
 9 
10         Scanner scanner=new Scanner(System.in);
11 //构建Scanner类的对象scanner，关联于标准输入流System.in
12         float sum=1;//用于存储结果
13         
14         //for循环实现
15         System.out.println("for循环实现阶乘");
16         System.out.print("输入阶乘值：");
17         int a=scanner.nextInt();
18         for(int i=1;i<=a;i++){
19             sum*=i;
20             System.out.print(i);
21             if(i<a) System.out.print("*");
22             }
23         System.out.println("="+sum);
24         
25         //do--while循环实现
26         System.out.println("\ndo--while循环实现阶乘");
27         int j=1;sum=1;
28         System.out.print("输入阶乘值：");
29         int S=scanner.nextInt();
30         do{
31             sum*=j;
32             System.out.print(j);
33             if(j<S) System.out.print("*");
34             j++;
35         }while(j<=S);
36         System.out.println("="+sum);
37         
38         //while循环实现
39         System.out.println("\nwhile循环实现阶乘");
40         System.out.print("输入阶乘值：");
41         int x=scanner.nextInt();
42         int l=1;sum=1;
43         while(l<=x){
44             sum*=l;
45             System.out.print(l);
46             if(l<x) System.out.print("*");
47             l++;
48         }
49         System.out.println("="+sum);
50         
51         //递归实现
52         System.out.println("\n递归实现阶乘");
53         System.out.print("输入阶乘值：");
54         int y=scanner.nextInt();
55         System.out.println("="+jie(y));
56         
57         System.out.println("\n以上，结束！");
58     }
59     static int jie(int b)
60     {
61         if(b==0)
62             return 1;
63         else 
64         {System.out.print(b);
65         if(b>1) System.out.print("*");
66             return b*jie(b-1);}
67         }
68 
69 }
70  

运行结果：