the program should include "c" language not "c++'

What happens if you simplify main so that it just calls SuNN with a fixed value, e.g.

Code:

int main()
{
  SuNN(5);
  return 0;
}

You might need to double-check the syntax of a for loop in your course notes. Your choice of expressions around the semicolons doesn't make a lot of sense currently.