[JAVA] 100! 階乘使用遞迴Method

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  • JAVA
  • 2008-11-30

摘要:[JAVA] 100! 階乘使用遞迴Method

利用遞迴完成階乘(100!),輸出在螢幕上。

JAVA:

01 import java.io.*;
02 import java.text.*;
03
04 public class test{  
05     public static void main(String args[]) throws Exception
06     {  //程式進入點
07   String getbr;
08   BufferedReader br= new BufferedReader(new InputStreamReader(System.in));
09   int x=0;
10   /*****請使用者輸入選項**********/
11   
12   while (x>=0)
13   {
14     System.out.print("請輸入要計算階乘的數字:");
15     getbr = br.readLine();
16     x=Integer.parseInt(getbr);
17     if (x<0)
18     {
19           System.out.println("謝謝!再見!");
20       continue;
21     }

22     //引用類別
23     DecimalFormat numberFormat = new DecimalFormat("#");
24     String s;
25     System.out.println(x+ "!="+ rfc(x));
26     System.out.print(x+ "!="+ String.format("%.2e\n",rfc(x)));//科學記號
27     System.out.println(x+ "!="+ numberFormat.format(rfc(x)));
28                 }
//while結束
29     }
//main 結束
30     private static double rfc(int g)
31     {
32   switch (g)
33   {
34   case 1:
35       return 1;
36       //break;
37   default:
38       return  g * rfc(g - 1);
39   }

40     }

41 }

42

輸出結果:

100!=9.33e+157
100!=93326215443944100000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000

執行結果畫面:


http://java.sun.com/j2se/1.4.2/docs/api/java/text/DecimalFormat.html
http://java.sun.com/j2se/1.4.2/docs/api/java/text/NumberFormat.html

範例下載:test.rar

小曼加油!!!

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