Constructors:
Special
function
Without
return type
Name
of class and constructor are same
Default constructors:
This constructor automatically created when we create
an object
No need to call
This constructor has no argument pass
#include<iostream>
using namespace std;
class employee
{
string name;
int employee_id;
int selary;
public:
employee()
{
cout<<"enter name"<<endl;
cin>>name;
cout<<"enter employee id"<<endl;
cin>>employee_id;
cout<<"enter selary"<<endl;
cin>>selary;
}
void display()
{
cout<<"-----------------------"<<endl;
cout<<"name "<<name<<endl;
cout<<"employee "<<employee_id<<endl;
cout<<"selary "<<selary<<endl;
cout<<"-----------------------"<<endl;
}
};
int main()
{
employee s2;
s2.display();
return 0;
}
Parameterized
constructor:
This type of constructor
has argument pass in the constructor
We call it and add
parameters
#include<iostream>
using namespace std;
class employee
{
string s_name;
int roll_no;
int s_marks;
public:
employee(string name,int roll ,int marks)
{
s_name=name;
roll_no=roll;
s_marks=marks;
}
void display()
{
cout<<"------------------------------"<<endl;
cout<<"name "<<s_name<<endl;
cout<<"roll no "<<roll_no<<endl;
cout<<"marks "<<s_marks<<endl;
cout<<"------------------------------"<<endl;
}
};
int main()
{
employee s("waqas",17,487);
s.display();
;
return 0;
}
Copy
constructors:
it used to
copy of one object to another
initialization of an object with another object called copy
constructor
We also need to call it for use
Syntax:
Class name (const class name & object
name)
#include<iostream>
using namespace std;
class student
{
string s_name;
int roll_no;
int s_marks;
public:
student (string name, int roll, int marks)
{
s_name=name;
roll_no=roll;
s_marks=marks;
}
student(student &s)
{
s_name=s.s_name;
roll_no=s.roll_no;
s_marks=s.s_marks;
}
void display()
{
cout<<"-----------------------------------"<<endl;
cout<<"name "<<s_name<<endl;
cout<<"roll no "<<roll_no<<endl;
cout<<"marks "<<s_marks<<endl;
cout<<"-----------------------------------"<<endl;
}
};
int main()
{
student s1("waqas",17,487);
student s3(s1);
cout<<"parameterized constuctor"<<endl;
s1.display();
cout<<"copy constutor"<<endl;
s3.display();
return 0;
}
