# Hierarchical Inheritance In C++

The process of deriving many classes from a base class is known as hierarchical inheritance In c++.

Syntax of Hierarchical inheritance:

``````class A
{
// body of the class A.
}
class B : public A
{
// body of class B.
}
class C : public A
{
// body of class C.
}
class D : public A
{
// body of class D.
}   ``````

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Let’s live example:

```#include <iostream>
using namespace std;
class Shape                 // Declaration of base class.
{
public:
int a;
int b;
void get_data(int n,int m)
{
a= n;
b = m;
}
};
class Rectangle : public Shape  // inheriting Shape class
{
public:
int rect_area()
{
int result = a*b;
return result;
}
};
class Triangle : public Shape    // inheriting Shape class
{
public:
int triangle_area()
{
float result = 0.5*a*b;
return result;
}
};
int main()
{
Rectangle r;
Triangle t;
std::cout << "Enter the length and breadth of a rectangle: " << std::endl;
int m = r.rect_area();
std::cout << "Area of the rectangle is : " <<m<< std::endl;
std::cout << "Enter the base and height of the triangle: " << std::endl;
cin>>base>>height;
t.get_data(base,height);
float n = t.triangle_area();
std::cout <<"Area of the triangle is : "  << n<<std::endl;
return 0;
}```

Output:

``````Enter the length and breadth of a rectangle:
23
20
Area of the rectangle is : 460
Enter the base and height of the triangle:
2
5
Area of the triangle is : 5 ``````