Headers
#include <iostream>
#using namespace std; |
Structure Example
Declare Structure |
struct Order {
int modelNumber;
string phone;
float cost;
}; |
Main Function, define the structure variable |
int main( ) {
Order item1; |
Give values to structure variables |
item1.modelNumber = 10;
item1.phone = "Samsung Galaxy S";
item1.cost = 1099.99; |
Display/Output structure members |
cout << "Order, " << item1.phone << item1.modelNumber;
cout << "This item costs: $" << part1.cost << endl;
} |
Output:
Order, Samsung Galaxy S10
This item costs: $1099.99 |
Whenever finished with output or line,
place 'end line' indicator: endl
Class Example: point.h
Declare class with the class name |
class Point
{ |
Provide the class specifiers, set as private |
private:
double x;
double y; |
Set x as the first variable, y as the second variable |
void set (double first, double second)
{
x = first;
y = second;
} |
Provide the class properties and methods, set as public
No-parameter constructor, when an object for this class is created, the Point class values (x and y) will be set to 0 |
public:
Point( ) : x(0.0), y(0.0)
{
cout << "New Point object created/instantiated." << endl;
} |
Alternatively, the above constructor can also be written as: |
Point( )
{
x = 0.0;
y = 0.0;
} |
A two parameter constructor, set the x and y values |
Point (double first, double second) : x(first), y(second)
{
cout << "New object, values (x,y) are << x << "," << y << endl;
} |
For returning individual values of x and y |
double getX( ) { return x; }
double getY( ) { return y; } |
Display the current values of x and y |
void display ( ) {
cout << x << "," << y << endl; } |
Overloading the function with two new doubles as input parameters |
void add(double first, double second) {
x += first;
y += second; } |
Overloading the function with another Point object as the input |
void minus(Point pp) {
x = x - pp.x;
y = y - pp.y ; } |
Add the destructor |
~Point ( ) {
cout << "Point object for x,y values of " << x << "," << y << "destroyed." << endl; } |
Overload the function with another Point object and return the result |
Point mult(Point pp1) {
Point pp2;
pp2.x = x * pp2.x;
pp2.y = y * pp2.y;
return p2;
} |
Class Example: point.cpp
#include "point.h" |
Main Function |
int main( ) {
Point ptA;
Point ptB(1.0, 3.0), ptC (5.0, 8.0);
ptB.add(6.0,2.0);
ptC.minus(ptB);
ptA = ptC;
Point ptD = ptB.mult(ptA);
ptA.display( );
return 0;
} |
Object Values:
ptA = (0.0,0.0); ptB(1.0, 3.0); ptC(5.0,8.0);
ptB.add(6.0,2.0)= (1.0+6.0, 3.0+2.0);
ptC.minus(ptB)= ((5.0-1.0),(8.0-3.0)) = (4.0,5.0);
ptA = new ptC value = (4.0,5.0);
ptD = ptB.mult(ptA) = ((4x7),(5x5)) = (28, 25); |
|
|
Note:
About Properties and Classes |
A property is a defined attribute of the object, for example properties for object Point include 'x' and 'y'
A member, often a function, is an action that is performed on the object and its properties.
class myClass {
private: property = value;
public: method { (action on value); }
}
main { myClass newObject; }
Internal and External Class Methods
If the Class methods are written externally, a prototype must be declared within the class first. |
Point (double first, double second) : x(first), y(second);
double getX( );
double getY( );
void display ( ); |
External syntax for returning class:
className :: className(any parameters) { } |
Point :: Point (double first, double second) : x(first), y(second) {
cout << "Object made with values x,y of " << x << "," << y << endl;
} |
External syntax for returning variable (or void):
returnDataType className :: methodName(any parameters) { } |
double Point :: getX( ) { return x; }
double Point :: getY { return y; }
void Point :: display ( ) {
cout << "point x,y : " << x << "," << y << endl; } |
Class Operator Overloading: Vector.h
Declare class with private array variable as property |
class Vector {
private:
double num[3]; |
Set initialization values for class property |
public:
Vector ( ) : num{0.0, 0.0, 0.0 } {}
Vector (double no1, double no2, double no3) {
num[0] = no1; num[1] = no2; num[2] = no3; }
void display ( ) {
cout << "[" << num[0] << ", " << num[1] << ", " << num[2] << "]" << endl; } |
Create prototypes for external class methods |
Vector operator++();
Vector operator++(int);
Vector operator--();
Vector operator+(Vector);
Vector operator-(Vector&);
friend Vector operator *(Vector&, Vector&);
double& operator[](int); |
Class Operator Overloading: Vector.cpp
#include "Vector.h" |
Vector Vector :: operator ++(){
return Vector((num[0] + 1), (num[1] + 1), (num[2] + 1)); }
Vector Vector :: operator++(int) {
num[0]++;
num[1]++;
num[2]++;
return Vector(num[0], num[1], num[2]); }
Vector Vector :: operator--(){
return Vector((num[0]-1), (num[1]-1), (num[2]-1)); }
Vector Vector :: operator + (Vector v) {
return Vector((num[0] + v.num[0]), (num[1] + v.num[1]), (num[2] + v.num[2])); }
Vector Vector :: operator - (Vector& v) {
return Vector((num[0] - v.num[0]), (num[1] - v.num[1]), (num[2] - v.num[2]));
}
Vector operator*(Vector& v1, Vector& v2) {
return Vector((v1.num[1] * v2.num[2]) - (v1.num[2] * v2.num[1]), (v1.num[2] * v2.num[0]) - (v1.num[0] * v2.num[2]), ((v1.num[0] * v2.num[1]) - (v1.num[1] * v2.num[0]))); }
double& Vector::operator[](int index) //friend operator {
if (index >= 3) {
cout << "Array index is out of bounds, exiting the program" << endl;
exit(1);
}
return num[index]; } |
Class Operator Overloading: Main.cpp
Create Object and use class methods |
int main(void) {
Vector a, b(3.0, 4.0, 5.0);
a[0] = 11.0;
a[1] = -15.0;
a[2] = 3.0;
Vector c(2.0,4.0,7.0);
(++c).display();
(c++).display();
(--c).display();
Vector d = a + b;
d.display();
d = a - b;
d.display();
d = a * b;
d.display();
d[5] = 5.0;
return 0;
} |
|
