c++day-4
DESCRIPTION
From these documents you will able to learn step by step, and you will be able to create projects as well as you can be good programmer or a good teacher or trainer on your filedTRANSCRIPT
Session Objectives
Define Class & Objects
Private ,Public Access Specifier
How to Create a Object
How to call the member Function
Scope Resolution Operator
SYNTAX : class<classname>
{
private :
datatype member1;
datatype member2;
public :
<retu_type> func_name1(arguments);
<retu_type> func_name2(arguments);
};
TO CREATE A NEW CLASS
create a object from the main()functions Syntax:
classname<objectname1, objectname2,..>;
For Example : class emp
{
private:
char name[25]; //Member Data
int empno;
float salary;
public:
void get_data() // Member Function
{
---------
}
void show_details()
{
-------------
------------
};
objectname.func_name(arguments);
Write a Program to calculate the area of a circle
using class & Object
#include<iostream.h>
#include<conio.h>
class raji
{
private:
int radius;
float area;
public:
void getdata()
{
cout<<"Enter the radius"<<endl;
cin>>radius;
}
void calculate() { area=3.14*radius*radius; } void showdata() { cout<<"The area of the circle is "<<area<<endl; } }; void main() { raji r; r.getdata(); r.calculate(); r.showdata(); getch(); }
Enter the Radius : 2 The area of the circle is
#include<iostream.h>
#include<conio.h>
class smallobj
{
private :
int s;
public :
void setdata(int d)
{
s=d;
}
void showdata()
{
cout<<endl<<"the Data is
"<<s;
}
};
void main()
{
smallobj a1,a2;
clrscr();
a1.setdata(2500);
a2.setdata(4000);
a1.showdata();
a2.showdata();
getch();
}
Class & Objects Example #include<iostream.h>
#include<conio.h>
class distance
{
private:
int feet;
float inches;
public :
void setdist(int ft,float in)
{
feet=ft;
inches=in;
}
void getdist()
{
cout<<endl<<"Enter Feet and Inches
Value:";
cin>>feet>>inches;
}
void showdist()
{
cout<<endl<<feet<<endl<<inches;
}
};
void main()
{
distance dist1,dist2;
clrscr();
dist1.setdist(11,6.25);
dist2.getdist();
dist1.showdist();
dist2.showdist();
getch();
}
#include<iostream.h>
#include<conio.h>
const int MAX=100;
class stack
{
private:
int st[MAX];
int top;
public :
stack() {
top=0; }
void push(int v) {
st [++top]=v; }
int pop()
{
return st[top--];
}
};
void main()
{
stack s1;
s1.push(11);
s1.push(22);
cout<<" Ist Data :"<<s1.pop();
cout<<" IInd Data :"<<s1.pop();
s1.push(33);
s1.push(44);
s1.push(55);
s1.push(66);
cout<<" III Data :"<<s1.pop()<<endl;
cout<<" IV Data :"<<s1.pop()<<endl;
cout<<" V Data :"<<s1.pop()<<endl;
cout<<" VI Data :"<<s1.pop()<<endl;
getch();
}
ARRAY OF OBJECTS I #include<iostream.h>
const int MAX=100;
class Distance
{
private:
int feet;
float inches;
public :
void get()
{
cout<<"\n Enter Feet Value :";
cin>>feet;
cout<<"\n Enter Inche Value :";
cin>>inches;
}
void show()
{
cout<<feet<<"\t"<<inches<<endl;
}
};
void main()
{
Distance dist[MAX];
int n=0;
char ans;
cout<<endl;
do
{
cout<<"\n Enter Distance "<<n+1;
dist[n++].get();
cout<<"\n Another Data [y/n]?";
cin>>ans;
}while(ans != 'n');
for(int j=0;j<n;j++)
{
cout<<"Distance Number "<<j+1<<"
Is ";
dist[j].show();
}
}
ARRAY OF OBJECTS II #include<iostream.h>
#include<conio.h>
class circle {
private:
int area, radius;
public:
void getdata() {
cout<<"Enter the radius
value"<<endl;
cin>>radius;
}
void calculate() {
area=3.14*radius*radius;
}
void show() {
cout<<"the area is "<<area<<endl;
}
};
void main() {
int i;
circle e[5];
for(i=0;i<5;i++)
{
e[i].getdata();
e[i].calculate();
e[i].show(); }
getch(); }
Output
Enter the radius value 1
The area is 3
Enter the radius value 2
The area is 12
Enter the radius value 3
The area is 28
Enter the radius value 4
The area is 50
Enter the radius value 4
The area is 50
Scope Resolution Operator (::)
The member function of
A program are defined outside
the boundary of the class using
the scope resolution operator(::) #include<iostream.h>
class circle {
private:
int radius;
float area;
public:
void getdata();
void get(int r);
void calculate();
void show();
};
void circle::getdata(){
cout<<"RADIUS"<<endl;
cin>>radius; }
void circle::get(int r) {
radius=r; }
void circle::calculate()
{
area=3.14*radius*radius;
}
void circle::show()
{
cout<<"Area"<<area;
}
void main() {
circle r;
r.getdata();
r.calculate();
r.show();
r.get(100);
r.calculate();
r.show();
}
RESULT :
ENTER THE RADIUS : 5
Area FOR 5=78.5
Area FOR 100=31400
Returning Values from class's
Memeber Function to main()
function
#include<iostream.h>
#include<conio.h>
class rectangle
{
private :
int length,breadth,area;
public :
void setdata(int a,int b)
{
length=a;
breadth=b;
}
int calculate()
{
return length*breadth;
}
};
void main()
{
rectangle r;
int area;
clrscr();
r.setdata(5,8);
area=r.calculate();
cout<<endl<<" Area is :"<<area;
getch();
}
Each class specification starts with the keyword “class”
The Class Specification must always end with a semicolon (;)
Data abstraction is the ability to create user-defined data
types for modeling real world objects using built-in data types.
Classes are used for data abstraction by hiding the
implementation of a type in the “private” part.
EXERCISES
1. Describe the use of Array of Objects?
2. List the various applications of Scope Resloution Operator?
3. Explain briefly Classes & Objects?
4. Describe the Array as Class member Data?