Question

I'm taking a C++ Object Oriented Programming course right now. My professor only gives us the word description of topics and I want to know what it would look like in code form. For example, I understand what classes, operations and inheritance are supposed to do but I want to know what they look like in an example of code.  

Answer 1

Syntax of class-
class class_Name
{
data member;
memeber function;
}
Example-Program for student information using class
Code
#include <iostream>
using namespace std;
class student //creation of class
{
private: // private data member
char name[30];
int rollNo;
  
public:
//member function to get student's information
void getdata(void);
//member function to display student's information
void display(void);
};

//definition of member function getdata(void) outside of the class
void student::getdata(void)
{
cout << "Enter name: " ;
cin >> name;
cout << "Enter roll number: ";
cin >> rollNo;
}

//definition of member function display(void) outside of the class
void student::display(void)
{
  
cout << "Name:"<< name << ",Roll Number:" << rollNo<<"\n";
}

int main()
{
student s1,s2; //creation of two objects objects
s1.getdata(); //calling function
s2.getdata(); //calling function
cout << "Student details:\n";
s1.display(); //calling function
s2.display(); //calling function
return 0;
}
Output-
Enter name: mukesh
Enter roll number: 120
Enter name: ramesh
Enter roll number: 121
Student details:
Name:mukesh,Roll Number:120
Name:ramesh,Roll Number:121

Inheritence-

Syntax of inheritence:

class base_class
{
//body of base class
};
class derived_class:access_mode base_class
{
//body of derived class
}
Program for multiplication of two numbers
code
#include <iostream>
using namespace std;
class base //base class
{
public:
int a;
void getdata() // function taking input the value of a
{
cout << "Enter the value of a = ";
cin >> a;
}
};
class mult : public base //derived class mult
{
private:
int b;
public:
void getdata1()
{
cout << "Enter the value of b = ";
cin >> b;
}
void product() // function for multiplication
{
cout << "Product = " << a * b;
}
};

int main()
{
mult x; //object of derived class
x.getdata();
x.getdata1();
x.product();
return 0;
} //end of program
Output-
Enter the value of a = 3
Enter the value of b = 4
Product = 12

Operator Overloading-
Syntax of Operator Overloading
returntype classname :: operator op (argument)
{
statement;
... ... ...
}
Program for unary operator loading
code
#include <iostream>
#include <conio.h>
using namespace std;
class sample
{
int a,b;
public:
void getdata() // member function definition inside the class
{
cout<<"Enter a and b: ";
cin>>a>>b;
}
void operator -() //operator function as a member function
{
a=-a;
b=-b;
}
void putdata()
{
cout<<"a="<<a<<endl<<"b="<<b<<endl;
}
};

int main()
{
sample x;
x.getdata();
cout<<"Before overloading unary minus operator"<<endl;
x.putdata();
-x;
cout<<"After overloading unary minus operator"<<endl;
x.putdata();
getch();
return 0;
}
Output-
Enter a and b: 5
6
Before overloading unary minus operator
a=5
b=6
After overloading unary minus operator
a=-5
b=-6