跳台阶

一只青蛙一次可以跳上1级台阶，也可以跳上2级。求该青蛙跳上一个n级的台阶总共有多少种跳法。

class Solution {
public:
int jumpFloor(int number) {
if(number==1) return 1;
if(number==2) return 2;
int fnum1 = 1, fnum2 = 2;
int num;
for(int i = 3; i <=number; i++){
num = fnum1 + fnum2;
fnum1 = fnum2;
fnum2 = num;
}
return num;
}
};