Passing Data in OO languages

You need to have context to do certain operations.  Like a logging class would need an open file 
handle to the log file.

1) Use a public void set(X newx) method and internally use a private X x member variable.

2) Use the ctor(X newx) and internally use a private X x member variable.

3) Require subclassing and internally use a protected abstract X get() method.

4) For each function that requires it, pass it in.  public void doSomething(X x);

5) Use a global.