How to convert a number to a string without losing form?

Question

C++ / C#

There is a number, for example 0.0000000000000001. When translated to string, it produces 1E-16.
How to convert a number to a string without converting the number to exponential form?

Answer 1

If the task is to get rid of the exponential form, then this solution is suitable

string formatted = String.Format("{0:F20}", value);