java实现：定义一个方法getFactorial求出n!的结果阶乘公式为n! = 123n

public class Factorial {
    public static void main(String[] args) {
        int n = 5;
        int factorial = getFactorial(n);
        System.out.println(n + "! = " + factorial);
    }
    
    public static int getFactorial(int n) {
        int factorial = 1;
        for (int i = 1; i <= n; i++) {
            factorial *= i;
        }
        return factorial;
    }
}

运行结果： 5! = 120