Data Structures Goal: organize data Criteria: facilitate efficient storage of data retrieval of data manipulation of data Process: select and design appropriate data types

Examples

Tradeoff

abstract data type (ADT)

implementation of an ADT

Simple Data Types (§2.2)

Boolean data

Character Data

Integer Data

Sign-magnitude representation

Two's complement representation

Biased representation

Problems with Integer Representation Limited Capacity -- a finite number of bits Overflow - addition or multiplication can exceed largest value permitted by storage scheme Underflow - subtraction or multiplication can exceed smallest value permitted by storage scheme Not a perfect representation of (mathematical) integers can only store a finite (sub)range of them

Real Data

Problems with Real Representation

C-Style One-Dimensional Arrays (§2.3)

Declaring arrays in C++

Subscript operator

Array Initialization

Initializations with no array size specified

Addresses

C-Style Multidimensional Arrays

Problems with C-Style Arrays Capacity cannot change. No predefined operations on non-char arrays. ® Must perform bounds checking, size restrictions, ... C-style arrays aren't self-contained. ® Must pass size (and/or capacity) to array-processing functions. Solution (OOP): Encapsulate array, capacity, size, and operations in a class. ® vector

A commercial for OOP: Two programming paradigms Object-oriented: ( C++, Java, and Smalltalk) Focuses on the nouns of a problem's specification Programmers: Determine what objects are needed for a problem and how they should work together to solve the problem. Create types called classes made up ofdata members and function members to operate on the data. Instances of a type (class) are called objects. Procedural: ( C, FORTRAN, and Pascal ) Action-oriented — concentrates on the verbs of a problem's specification Programmers: Identify basic tasks to be performed to solve problem Implement the actions required to do these tasks as subprograms (procedures/functions/subroutines) Group these subprograms into programs/modules/libraries, which together make up a complete system for solving the problem