1. Modifying Objects Assignment operation Assignment conversions
Assignment precedence and associativity
Extraction operations
CONST declarations
Compound assignment operations
Input with cin
Increment and decrement operation
strings
5/6/2019
Y K Choi

2. Memory Depiction
float y = 12.5;
memory

3. Memory Depiction
float y = 12.5;
int Temperature = 32;

4. Memory Depiction float y = 12.5; int Temperature = 32;
char Letter = 'c';

5. Memory Depiction float y = 12.5; int Temperature = 32;
char Letter = 'c';
int Number;

6. Assignment -- = The operator is =
The operator stores a value into an object
Example: int x = 3;
int i = 4; //4 bytes for this variable i
float weight = 120.4; //floating point (4 bytes for single precision)
unsigned int i = 4; //no negative (4 bytes)
Note that it is better to define unsigned for looping such as for unsigned i = … as it is faster.

7. Assignment Conversions
#include <iostream>
#include <string>
using namespace std;
void main() {
short s1 = 0;
long i2 = 65536;
s1 = i2;
cout<<"i2 is " << i2 <<endl;
cout <<"s1 is " << s1 <<endl; }
S1 is 0 instead of 65536, interesting, as 16 bits are reserved for s1, the highest 16 bits (16 out of 32) is chopped off.

8. Screen dump – note the value of s1

9. It means pi is always 3.1416 within the program.
CONST definition
The CONST definition is:
const Type Identifier = Expression;
const float light_speed = 3.0e8; //the speed of light
const float pi = ; //the pi
It means pi is always within the program.

10. Input statements Cin (pronounced as C in) and operator >>
Example
int x; //define i as an integer
cin >> i; //get the value from keyboard and load into I
char cvalue; //define cvalue as char
cin >> cvalue; //load a single byte (8 bits) into cin

11. Screen dump

12. Note the operators used, it optimises the programs
Compound assignments
int j = 7;
int i = 5;
int k = 3;
i /=k; //i becomes i = i/k
j *= i; // j = j *i
j %= i; //j = j %i
Note the operators used, it optimises the programs

13. Increment and Decrement
Operator ++ and –
Example
After the operation, i becomes 4
Before this operation, i becomes 4
int i = 3;
++i;
cout <<“i is “ <<i <<endl;
int i = 3;
i++;
cout <<“i is “ <<i <<endl;
Both will display the values of 4.

14. The operation is j * (i +1)
How about j *i++;
Screen dump
The operation is j * (i +1)

15. Nonfundamental Types
Nonfundamental as they are additions to the language
C++ permits definition of new types and classes
A class is a special kind of type
Class objects typically have
Data members that represent attributes and values
Member functions for object inspection and manipulation
Members are accessed using the selection operator (.)
j = s.size();
Auxiliary functions for other behaviors
Libraries often provide special-purpose types and classes
Programmers can also define their own types and classes

16. Examples Standard Template Library (STL) provides class string
EzWindows library provides several graphical types and classes
SimpleWindow is a class for creating and manipulating window objects
RectangleShape is a class for creating and manipulating rectangle objects

17. Class string Class string Some definitions
Used to represent a sequence of characters as a single object
Some definitions
string Name = "Joanne";
string DecimalPoint = ".";
string empty = "";
string copy = name;
string Question = '?'; // illegal

18. Nonfundamental Types
To access a library use a preprocessor directive to add its definitions to your program file
#include <string>
The using statement makes syntax less clumsy
Without it
std::string s = "Sharp";
std::string t = "Spiffy";
With it
using namespace std; // std contains string
string s = "Sharp";
string t = "Spiffy";

19. Screen dump

20. Summary Assignment conversions Assignment precedence and associativity
Extraction operations
CONST declarations
Compound assignment operations
Input with cin >> x
Increment and decrement operation ++ and --
Strings