Complexity of Loop Increment of 2

Question

What is the time complexity of the following loop?

for(int i=1; i<=n; i=i*2){
    System.out.println("*");
}

is it logarithmic?

Answer 1

The algorithm as shown would be O(log n)

Since the number of iterations would be log2(n), or log10(n)/log10(2)

Answer 2

It's O(log n) because you are doubling the value of i on each iteration: 1, 2, 4, 8, ...

If n is 2^x the loop will terminate after log₂(2^x) + 1 = x + 1 iterations.