1. Structured Data (Lecture 07)
By:
Dr. Norazah Yusof
FSKSM, UTM

2. Data Types
Primitive data types - defined as a basic part of the language.
Abstract Data Type (ADT) – created by the programmer and is composed of one or more primitive data types.
Have own range (or domain) of data and own set of operations that may be performed on them.
bool
int
unsigned long int
char
long int
float
unsigned char
unsigned short int
double
short int
unsigned int
long double

3. Abstract Data Type
Example: Write a program to simulate a 12-hour clock.

4. Abstract Data Type
Example: Write a program to simulate a 12-hour clock.
The program could contain three ADTs:
Hours
Minutes
Seconds
The range of values
Hours : integers 1 through 12
Minutes : integers 0 through 59
Seconds : integers 0 through 59
If an Hours object is set to 12 and then incremented, it will then take on the value 1.
If an Minutes object or Seconds object is set to 59 and then incremented, it will then take on the value 0.

5. Combining Data into Structures
Structure – group several variables together into a single item
Declaration format of a structure:
struct tag {
variable declaration;
//more declaration; };

6. Example: Structure declaration of Time
struct Time {
int hours;
int minutes;
int seconds; };

7. Definition of Structure Variables
Structure declaration does not define a variable. It only create a new data type.
Variable(s) of this type can be defined.
Format:
tag varname;
Example: Define structure variable named now of type Time.
Time now;

8. Memory layout of structure variable, now
hours
minutes
seconds
Time
Members

9. Example 2
Declare a structure named PayRoll that has the following members:
Employee number: integer
Employee’s name : array of characters
Hours worked : floating point numbers
Hourly pay rate : floating point numbers
Gross pay : floating point numbers
Define three PayRoll variables: deptHead, foreman, associate
Draw the memory layout.

10. Example 2: Structure declaration of PayRoll and variables definition.
cont int SIZE = 25;
struct PayRoll {
int empNumber;
char name[SIZE];
double hourWork, hourPayRate, grossPay; };
PayRoll deptHead, foreman, associate;

11. Memory Layout of PayRoll variables
empNumber
name
hourWork
deptHead
hourPayRate
grossPay
foreman
empNumber
name
hourWork
hourPayRate
grossPay
associate
empNumber
name
hourWork
hourPayRate
grossPay

12. Assessing Structure Members
Dot operator (.) allows you to access structure members in a program.
Example 1: Access the empNumber member of deptHead by assigning value of 475 to it.
Example 2: Access the name, hourWork, and hourPayRate by assigning values of Muhammad, 200, and 15 to it, respectively. Then, assign the value to the grossPay by assigning the result of arithmetic operation: hourWork x hourPayRate
Example 3: Display the contents of deptHead’s member

13. Assessing Structure Members
deptHead.empNumber = 475;
strcpy(deptHead.name, "Muhammad");
deptHead.hourWork = 200;
deptHead.hourPayRate = 15;
deptHead.grossPay =
deptHead.hourWork * deptHead.hourPayRate;

14. Assessing Structure Members
Example 3: Display the contents of deptHead’s member.
Cannot display the content by passing the entire variable:
cout << deptHead; //will not work!

15. Assessing Structure Members
Example 3: Display the contents of deptHead’s member. Each member must be passed to cout, separately.
cout << "Name: " << deptHead.name << endl;
cout << "ID Number: " << deptHead.empNumber << endl;
cout << "Hours worked: " << deptHead.hourWork;
cout << endl;
cout << "Hourly pay rate: " << deptHead.hourPayRate;
cout << "Gross pay: " << deptHead.grossPay << endl;

16. Read data from the keyboard
Change Example 2: Read data from the keyboard for the members name, hourWork, and hourPayRate.

17. Read data from the keyboard
cout << "Enter the employee number:";
cin >> deptHead.empNumber;
cout << "Enter the employee’s name:"; cin.ignore(); //ignore the next character in
// the input buffer.
cin.getline(deptHead.name, SIZE);
cout << "How many hours did the employee work?";
cin >> deptHead.hourWork;
cout << "What is the employee’s hourly pay rate?";
cin >> deptHead.hourPayRate;

18. Comparing Structure Variables
Cannot perform comparison operations directly on structure variables.
if (deptHead == foreman) //Error!
To compare between two structures, need to compare individual members, as follows:
if (deptHead.hourWork == foreman.hourWork) :
if (strcmp(deptHead.name,foreman.name) == 0)

19. Initializing a Structure
The members of a structure variable may be initialized with starting values when it is defined.
Example: Declare a structure variable named CityInfo. Define a variable named location with initialization values.
structure CityInfo {
char cityName[30];
char state[3];
long population;
int distance; };

20. Initializing a Structure
structure CityInfo {
char cityName[30];
char state[3];
long population;
int distance; };
CityInfo location = {"Johor Bahru", "JH", 80000, 280};
CityInfo location = {"Kuantan", "PH", 50000};
CityInfo location = {"Ipoh", "PK"};
CityInfo location = {"Kuala Terengganu"};
CityInfo location = {"Seremban", "NS", ,68};//illegal!