Difference between Single and Multiple Inheritance in C++

Single inheritance and multiple inheritance are two inheritance mechanisms in C++ that allow a class to acquire properties and behaviors from other classes. The main difference lies in the number of base classes from which a derived class inherits.

• Single inheritance involves one base class and one derived class.
• Multiple inheritance allows a derived class to inherit from two or more base classes.
• Both improve code reuse but differ in complexity and design flexibility.

Single Inheritance

Single Inheritance is a type of inheritance in which a derived class inherits the properties and methods of a single base class. It allows code reuse and establishes a hierarchical relationship between classes.

• One child class inherits from one parent class.
• Enables code reuse and reduces code duplication.

Syntax

class Derived : public Base {

// Class body

};

Example: Program to illustrate Single Inheritance

#include <iostream>
using namespace std;
class A {
public:
    int k = 1000;
    float salary = 80000;
};
class B : public A {
public:
    float bonus = 8000;
    void ts()
    {
        cout << "Total salary.." << (salary + bonus)
             << endl;
    }
};
int main()
{
    B b1;
    cout << "Salary:" << b1.salary << endl;
    cout << "Bonus:" << b1.bonus << endl;
    b1.ts();
    return 0;
}

Salary:80000
Bonus:8000
Total salary..88000

Explanation: Class B inherits the members of class A and can directly access them according to the inheritance access specifier.

Multiple Inheritance

Multiple Inheritance is a type of inheritance in which a derived class inherits properties and methods from more than one base class. C++ supports multiple inheritance directly, allowing a class to combine functionalities from multiple parent classes.

• A single derived class can inherit from multiple base classes.
• Helps reuse code and combine features from different classes into one class.

Syntax

class Derived : public Base1, public Base2 {

// Class body

};

Example: Program to illustrate Multiple Inheritance

#include <iostream>
using namespace std;
class A {
protected:
    int a;

public:
    void get_a(int n) { a = n; }
};

class B {
protected:
    int b;

public:
    void get_b(int n) { b = n; }
};

class C : public A, public B {
public:
    void display()
    {
        cout << "The value of a is : " << a << endl;
        cout << "The value of b is : " << b << endl;
        cout << "Product of a and b is : " << a * b;
    }
};

int main()
{
    C c;
    c.get_a(10);
    c.get_b(20);
    c.display();

    return 0;
}

The value of a is : 10
The value of b is : 20
Product of a and b is : 200

Explanation: Class C inherits members from both classes A and B, allowing it to use functionality from both base classes.

Single Inheritance Vs Multiple Inheritance

Related Article: Inheritance in C++