java例子3：计算阶乘

[root@gdc1000 java]# cat Factorial.java
public class Factorial {
public static void main(String[] args) {
int input = Integer.parseInt(args[0]);
double result = factorial(input);
System.out.println(result);
}

public static double factorial(int x) {
if(x < 0)
return 0;
double fact = 1.0;
while ( x > 1) {
fact = fact * x;
x = x - 1;
}
return fact;
}
}

[root@gdc1000 java]#