Copyright protects the fixed tangible expression of an idea – not the idea itself. This means that no one can use your code without permission, but they can independently develop their own code that will accomplish the same objective.
The copyright holder has the right to:
Reproduce or copy the work, Create derivative works, Distribute the work, Perform the work in public, Display the work in public, Digital transmission performance. Refer to the US Copyright Office at www.copyright.gov for additional details.