CIS3355: Business Data Structures
Fall, 2008
 

Basic Data Types
(Chapter 2 in the text).

In this section, we consider two new basic data types: integers, and reals (or floating point numbers). We also continue our discussion of the data type which we introduced in the previous chapter: characters. All of these data types are, in turn, composed of bits.

Although we refer to these data types as basic, they are, as we saw before, also abstract data types. Keep in mind, that as far as the computer is concerned, they are stored as high and low voltages. How we group them together, and how we interpret the groupings, is totally up to us (or at least the language designers). Must the sequence of bits 01000001 be interpreted as the character ‘A’? Of course not. It is just a convention that we understand (unless you are using EBCDIC). The same holds true for our interpretation of basic data types. For example, we later talk about the sign-bit being the leftmost bit (if that doesn’t make sense right now, it will). Must it be that way? No, we could have made it the rightmost bit (although it might change the way we manipulate the bits)

This is an extremely important Section. These basic data types are the building blocks for all of the following abstract data types to come. At times, we may seem over repetitious, but that is only because we wish to emphasize the importance of these data types.