Climbing Stairs

You are climbing a stair case. It takes n steps to reach to the top.

Each time you can either climb 1 or 2 steps. In how many distinct ways can you climb to the top?

class Solution {
public:
    int climbStairs(int n) {
        int step[n];
        step[0]=1;
        step[1]=1;
        for(int i=2;i<=n;i++)
            step[i]=step[i-1]+step[i-2];
        return step[n];
    }
};