递归和阶乘

class RecursionDemo

{

public static void main(String[] args)

{

//阶乘

System.out.println(factorial(5));

//递归调用

System.out.println(factorial2(5));

}

//递归算法（调用）

public static int factorial2(int num)

{

if(num==1)

{

return 1;

}

return num*factorial2(num-1);

}

//阶乘

public static int factorial(int num)

{

int sum = num;

int i = sum - 1;

do

{

sum*=i;

i–;

}

while (i>1);

return sum;

}

}