External environment refers to the major factors and forces outside the organization that have the potential to significantly affect the performance of an organization. External environment is divided into two parts i.e. mega environment or general environment and specific or task environment.
_tcscat is a C function, to concatenate C-style strings; CString is a class (which has built in concatenation via operator+), not a C-style string.
Refactoring is the process of improving your code after it has been written by changing the internal structure of the code without changing the external behavior of the code. Visual C# provides the following refactoring commands on the Refactoring menu: Extract Method Refactoring (C#).