int fib(int k)
{
if (k == 0 || k == 1)
return 1;
int first = 1;
int second = 1;
int sum = 0;
k -= 1;
while (k--)
{
sum = first + second;
second = first;
first = sum;
}
return sum;
}
int fib1(int k)
{
assert(k>=0);
if (k == 1 || k == 0)
return 1;
int sum = fib1(k - 1) + fib1(k-2);
return sum;
}
int main()
{
printf("%d\n", fib(1));
system("pause");
}
