Code should really compile without warnings
warning: return type of ‘main’ is not ‘int’
The use of unspecified argument lists is generally not considered good practice.
Run the code through something like astyle and it will indent it for you, and add braces if that's your style. Note that it's called 'artistic style' not 'professional style' as it's designed to make the code look nice, and activity which rarely adds as much value as it costs if done by paid employees.
Professionals do it for the money. If your job is to make a one-off program which does as little as this does, then there isn't much point adding that much more comments, using more explanatory variable names or manually tidying up the formatting. Documentation, record of design history and intent, clearly defined sub-system boundaries all matter on larger systems, but they are techniques for managing complexity. As a professional, your job is add the most value for the least cost. Quality, maintainability and testibility are values, as well as functionality; which values the organisation you work for weight the most will determine what you focus on.
