OO - Another Perspective

Another way to look at it is an issue of contexts. This is not usually explicitly discussed in OO texts.

A C function can see variables that are in the following scopes:

1. Local scope
2. Parameters
3. Global scope

A C++ class method can see variables that are in the following scopes:

1. Local scope
2. Parameters
3. Class scope
4. Global scope

A C++ instance method can see variables that are in the following scopes:

1. Local scope
2. Parameters
3. Instance scope
4. Class scope
5. Global scope

So at some level classes and instances just let a programmer create groups of variables that can be carted around together and be seen by functions that will use them.