1. Enumeration used to make a program more readable
associates a set of programmer defined values with the integer values 0, 1, 2, - -
Example
enum Suit {CLUBS, SPADES, HEARTS, DIAMONDS};
Suit mySuit = HEARTS;
if (mySuit == SPADES) ---
switch (mySuit) { case CLUBS: case SPADES: ---

2. typedef statement
used to declare a new name (synonym) for an already existing type
const int SIZE = 100;
typedef int intArrayType[SIZE];
intArrayType numberList;
usually given global (file) scope
used to make a program easier to modify

3. a function (procedure)
----
Func (arguments)
---
Return
value
Return_type Func(parameters)
code to perform
a task (carry
out an algorithm)

4. Parameters C parameters are either values or pointers
value parameters
reference parameters
constant reference parameters
array parameters
Java parameters are either
primitive types - parameter is a copy of the argument (argument cannot be changed)
objects - parameter is an alias for the argument (argument can be changed)

5. C and C++ Parameters C++ parameters are either
value - (type param_name)
parameter is a copy of the argument, thus argument cannot be modified
reference - (type & param_name)
parameter is an alias for the argument, thus argument is modified if parameter is modified
constant reference - (const type & param_name)
parameter is an alias for the argument, but compiler disallows assignment to parameter

6. C and C++ parameter passing
void myFunction (int val, int & ref, const int & constref) {
--- } v 36
myFunction (v, r, cr); r 25 cr 6 36
val
ref
activation record
(memory space)
created when
myFunction is
called
constref

7. Java parameter passing
public void myMethod (int number, SomeClass myObj) {
--- }
obj.myMethod (intArg, objArg); 36
intArg
objArg
number
myObj 36
activation record
(memory space)
created when
myMethod is
called

8. Decomposition Example
main
Instruct
GetEmployee
Info
GrossWages
Compute
NetPay
Print
EmpInfo

9. /* Program to compute wages for several employees.
Written at ___________ by _________________-
Input: Id-number, number of dependents, hours worked,
and hourly rate for each of several employees
Output: Id-number, hours worked, gross pay, taxes withheld and net pay
____________________________________________________*/
#include <iostream>
#include <iomanip>
using namespace std;
void Instruct ( );
void GetEmployeeInfo (int & empNumber, int & dependents,
double & hours, double & rate, bool & done);
double GrossWages (int dependents, double hours, double rate);
void ComputeNetPay (double grossPay, int dependents,
double & tax, double & netPay);
void PrintEmpInfo (int idNumber, double hours, double grossPay,
double taxes, double netPay);
int main ( ) { }

10. int main ( ) {
int idNumber, // employee's id-number
numDependents; // number of dependents
double hoursWorked, // hours worked this pay period
hourlyRate, // dollars per hour
grossPay, // pay before taxes
taxWithheld, // amount of tax withheld
netPay; // grossPay - tasWithheld
bool endOfData; // signals end of data
Instruct ( );
for ( ; ; )
GetEmployeeInfo (idNumber, numDependents, hoursWorked,
hourlyRate, endOfData);
if (endOfData) break; // MUST BE CHANGED!!
grossPay = GrossWages (numDependents, hoursWorked, hourlyRate);
ComputeNetPay (grossPay, numDependents, taxWithheld, netPay);
PrintEmpInfo (idNumber, hoursWorked, grossPay, taxWithheld, netPay); }
return 0;

11. int main ( ) {
int idNumber, // employee's id-number
numDependents; // number of dependents
double hoursWorked, // hours worked this pay period
hourlyRate, // dollars per hour
grossPay, // pay before taxes
taxWithheld, // amount of tax withheld
netPay; // grossPay - tasWithheld
// bool endOfData; // signals end of data
Instruct ( );
while (GetEmployeeInfo (idNumber, numDependents, hoursWorked,
hourlyRate))
// if (endOfData) break; // TO BE CHANGED!!
grossPay = GrossWages (numDependents, hoursWorked, hourlyRate);
ComputeNetPay (grossPay, numDependents, taxWithheld, netPay);
PrintEmpInfo (idNumber, hoursWorked, grossPay, taxWithheld, netPay) }
return 0;

12. Change Needed?
void GetEmployeeInfo (int & empNumber, int & dependents,
double & hours, double & rate, bool & done);
bool GetEmployeeInfo (int & empNumber, int & dependents,
double & hours, double & rate);

13. /* bool GetEmployeeInfo (int & empNumber, int & dependents,
double & hours, double & rate)
Purpose: read information for one employee
Precondition(s): none
Postcondition(s): The four parameters have been assigned values
Returns: false if end of data reached; true otherwise */
bool GetEmployeeInfo (int & empNumber, int & dependents, {
cout << "\nEnter employee number (0 to stop): ";
cin >> empNumber;
if (empNumber == 0)
return false;
cout << "Enter # of dependents, hours worked, and hourly rate for "
<< empNumber << ": ";
cin >> dependents >> hours >> rate;
return true; }

14. /* double GrossWages (int dependents, double hours, double rate)
Purpose: compute gross wages as determined by number of hours
employee worked plus a dependency allowance for each
dependent.
Precondition(s): dependents, hours and rate >= 0
Postcondition(s): none
Returns: Gross wages */
double GrossWages (int dependents, double hours, double rate) {
const double DEP_ALLOWANCE = 100; // bonus per dependent
double wages; // wages earned
if (hours <= 40) // no overtime
wages = hours * rate;
else // overtime
wages = 40 * rate * rate * (hours - 40);
return wages + DEP_ALLOWANCE * dependents; }

15. /* void Instruct ( )
Purpose: Display instructions to the user
Precondition(s): none
Postcondition(s): instructions have been displayed on the screen
Returns: nothing
**********************************************************************************/
/* void ComputeNetPay(double grossPay, int dependents,
double & tax, double & netPay)
Purpose: compute taxes withheld and net pay
Precondition(s): grossPay and dependents are valid
Postcondition(s): tax and netPay have been assigned computed values
************************************************************************************/
/* void PrintEmpInfo( int idNumber, double hours, double grossPay
double taxes, double netPay)
Purpose: display payroll information regarding one employee
Precondition(s): idNumber, hours, grossPay, taxes and netPay are valid
Postcondition(s): payroll information has been displayed on the screen
*************************************************************************************/

16. Programming & Problem Solving
Real world
results
Real world
problem
PROBLEM DOMAIN
PROGRAM DOMAIN
Representation
of results
Representation
of real world
problem
Processing algorithms

17. Variables (data objects)
Components of a data object
name (programmer defined)
address (memory location)
type
value (determined by interpretation of the sequence of bits stored in memory)
type name [= value];

18. Types predefined (built-in) vs programmer defined
simple (fundamental) vs structured
type of a data object determines
number of bytes used to store the value
interpretation of the bit pattern stored in those bytes
possible operations
data abstraction refers to the separation of the use of a data type from the implementation details

19. C++ Types C++ Standard Library classes Fundamental Types
valarray
vector
deque
list
set
map
multiset
multimap
stack
queue
string
bitset
istream
ostream
iostream
ifstream
ofstream
fstream
Structured Types
void
Arithmetic
pointers
array
Integral
Floating point
bool
complex
(reals)
struct
union
float
priority_queue
Characters
Enumerations
Integers
double
long double
char
int
unsigned char
short int
signed char
long int
unsigned
unsigned short
unsigned long

20. C++ arrays groups data items of same type under one name
double Numbers[4];
int List = {45, 63, 22};
individual items accessed by indexing
Numbers[2] = 85.3;
first array element is at index position 0
C++ arrays are not objects
no length data member
number of elements is determined either
at compile-time (both examples above)
at run-time (coming later)

21. C and C++ array implementation
array name is a variable whose value is the base address of the array, i.e. a pointer variable
accessing an individual element involves calculating its address
base_address + index * element_size
b b+1 b+2 b+3 b b b+12
List[0] List[1] List[2]
List 45 63 22

22. Alternative Syntax Given: int List = {45, 63, 22};
first element can be accessed by
List[0];
*List; // * is the dereferencing operator
second element can be accessed by
List[1];
*(List + 1);
what is the value of List?
always use the indexing notation

23. C++ array parameters void func (double A[ ], int N) { --- } 4 4 const
arguments provided when
func is called
activation record
(memory space)
created when
func is called A N 4
Numbers N 4

24. C++ structs struct - group of data items of different types
struct person { string Name; int Age; };
person is a type grouping together 2 data members
person OneStudent; //represents 1 person
person Class[25]; //represents 25 persons
dot operator (.) used to access members
Class[i].Age
struct to struct assignments are legal
Class[i] = Class[i+1];

25. Creating New C++ Types enumeration typedef struct class
allows defining your own set of values for a scalar type
typedef
allows for defining a synonym or alias for an existing type
struct
allows a variable to have multiple values of different types
class
allows encapsulating data members and operations

26. C++ strings early versions of C++ used “C-style strings”
array of char with a special character (null character) marking the end
<string.h> or <cstring> have functions to manipulate C-style strings
C++ standard library provides the class string
#include <string>
use C++ string class, not C-style strings