Climbing Stairs

Description:

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?

Code:

int climbStairs(int n) {
if (1==n)
return 1;
else if (2==n)
return 2;
else
{
int p = 1, q = 2, result = 0;
for (int i = 3; i <= n; i++)
{
result = p + q;
p = q;
q = result;
}
return result;
}
}