1 package com.jdk7.chapter1;
2
3 public class Factorial {
4 /**
5 * 计算n!的值，利用公式n×(n-1)×(n-2)×(n-3)×...×3×2×1
6 * 注：当n大于17时n!会超出long的取值范围
7 */
8 public long getFactorial(
int n){
9 if(n<0 || n>17
){
10 System.out.println("n的取值区间为[0,17]"
);
11 return -1
;
12 }
else if(n==0
){
13 return 1
;
14 }
else{
15 long result = 1
;
16 for(;n>0;n--
){
17 result *=
n;
18 }
19 return result;
20 }
21
22 }
23
24 public static void main(String[] args) {
25 Factorial f =
new Factorial();
26 System.out.println(f.getFactorial(4
));
27 System.out.println(f.getFactorial(17
));
28 System.out.println(f.getFactorial(18
));
29 System.out.println(f.getFactorial(0
));
30 System.out.println(f.getFactorial(-2
));
31 }
32
33 }
34
35 执行结果：
36 24
37 355687428096000
38 n的取值区间为[0,17
]
39 -1
40 1
41 n的取值区间为[0,17
]
42 -1
转载于:https://www.cnblogs.com/celine/p/8232881.html
相关资源：计算阶乘matlab算法
