//方法一
var factorial = function factorial(i,a){
a = a || 1;
if(i<2){
return a;
}
// return factorial(i-1,a*i);
return factorial(i-1,a*i);
};
console.log(factorial(100));
//方法二
function fac(n){
return n>1? n*fac(n-1):1;
}
console.log(fac(100));
