1. Structures - Part II aggregate operations arrays of type struct
nested structures
compared to classes

2. Aggregate Operations Operation Arrays Structs
I/O No (except strings) No
Assignment No Yes
Arithmetic No No
Comparison No No
Parameter pass. Ref. only Either value or ref.
Funct. return value No Yes

3. Arrays of Structures struct Salaried { char dept[5]; int salary;
int vac_days; };
// array of 20 elements, each of type Salaried
Salaried emp[20];

4. Arrays of Structures ... emp[0].dept = “Purc”; emp[0].salary = 34560;
emp[0].vac_days = 14;
...
emp[2].salary = 32100;
emp[2].dept = “Ship”;
emp[2].vac_days = 10; …
emp[19].dept = “Acct”;
emp[19].salary = 22500;
emp[19].vac_days = 12;

5. Arrays of Structures struct Payroll { int id; char name[15];
double payrate; };
// an array of 3 records of type Payroll
Payroll employee[3];

6. Arrays of Structures Payroll employee[3] = { {11, “Begay”, 7.25},
// load array -- there are other ways to load the array
Payroll employee[3] = { {11, “Begay”, 7.25},
{12, “Gioseffi”, 6.50},
{13, “Marra”, 9.00} };
// display array
for(ndx = 0; ndx < 3; ndx++)
cout << ‘\n’ << employee[ndx].id
<< setw(20) << employee[ndx].name
<< setw(20) << employee[ndx].payrate;

7. Arrays of Structures
struct Payroll { int id; char name[15]; double payrate; };
// prototypes void loadarray(Payroll [3]); void showarray(Payroll [3]); *

8. Arrays of Structures void main()
{ //declare array of 3 records of type Payroll
// and initialize the first record
Payroll employee[3] = { 11, "Begay", 7.25 };
loadarray(employee); // calls
showarray(employee);
cout << endl<<endl; // for formatting
} // end main()

9. Arrays of Structures
// load array - data typically entered via file input
void loadarray(Payroll staff[3])
{ // begin at 1 because [0] already entered
for(int ndx = 1; ndx < 3; ndx++)
{ cout << "Enter the ID, name, and pay rate: ";
cin >> staff[ndx].id >> staff[ndx].name
>> staff[ndx].payrate;
cout << endl; }

10. Arrays of Structures void showarray(Payroll staff[3]) {
cout << setiosflags(ios::fixed)
<< setprecision(2);
for(int ndx = 0; ndx < 3; ndx++)
cout << '\n' << setw(5) << staff[ndx].id
<< setw(13) << staff[ndx].name
<< setw(10) << staff[ndx].payrate; }

11. In Class Assign. 3 Element at. num at. mass density
tungsten (W)
sulfur (S)
carbon (C)
Write the plan first.
9. Write a program which:
a. creates an array of structures
b. uses a global constant for the array size
c. contains functions to load and to display
d. format similar to the above chart

12. In Class Assign. 3-ans. #include<iostream.h> void main()
#include<iomanip.h>
struct Element
{ char symbo;
int at_num;
double at_mass;
double density; };
const int ARR_SIZE = 3;
void loadarray(Element [ARR_SIZE ]);
void showarray(Element [ARR_SIZE ]);
void main()
{ //declare array - type Element
Element atom[ARR_SIZE ];
loadarray(atom); // calls
showarray(atom);
cout << endl<<endl;
} // end main()

13. Nested Structures * struct Date { int month; int day; int year; };
struct vital_Data
{ char name[15];
char dept[10];
int ID;
Date birth; // Date must be previously defined
double payrate; }; *

14. Nested Structures vital_Data Courtney; // declaration of an object
// assignments of data to an object
Courtney.name = “Lawrence”;
Courtney.dept = “personnel”;
Courtney.ID = 1234;
Courtney.birth = {10, 25, 87}; // this is a struct
Coutrney.payrate = 12.75;

15. Nested Structures
1. Write the cin statements for the department and the birthday.
2. Write the cout statements for the department and the birthday.

16. Nested Structures personnel[ndx].name; personnel[ndx].dept; * * * * *
void loadarray(vital_Data personnel[ARR_SIZE ]) {
for(int ndx = 1; ndx < ARR_SIZE ; ndx++)
{ cout << "\nEnter the name: ";
cin >>
cout << "Enter the department: ";
cout << "Enter the id# and the payrate: ";
cin >> >>
cout << "Enter the birth date (dd mm yy) ";
>>
>> } }
personnel[ndx].name;
personnel[ndx].dept;
personnel[ndx].ID
personnel[ndx].payrate;
personnel[ndx].birth.day
personnel[ndx].birth.month
personnel[ndx].birth.year;
* * *
* *

17. Formatted Output ID# name department birthday payrate
1234 Lawrence personnel 10/ 5/
765 Newman shipping 2/29/
cout << setiosflags(ios::fixed | ios::right);
for(int ndx = 0; ndx < ARR_SIZE ; ndx++)
cout << '\n' << setw(5) << setprecision(0) << personnel[ndx].ID
<< setw(12) << personnel[ndx].name
<< setw(11) << personnel[ndx].dept
<< setw(5) << personnel[ndx].birth.day <<'/'
<< setw(2) << personnel[ndx].birth.month <<'/'
<< setw(2) << personnel[ndx].birth.year
<< setw(7) << setprecision(2) << personnel[ndx].payrate;

18. Structure vs. Class By default: struct have public member variables
class have private member variables

19. Class Class syntax: class Classname { public:
list of function prototypes
private:
list of private variable declarations };

20. Class An example: class Date { public: private: int day; int month;
int year; };

21. Imagination is more important than knowledge.
Albert Einstein