In this program, You will learn how to find the area perimeter of a rectangle using a virtual function in C++.

```
virtual void calculate() {
//statement
}
```

## Example: How to find the area perimeter of a rectangle using a virtual function in C++.

```
#include<iostream>
using namespace std;
class First {
public:
virtual void calculate() {
cout << "Area Perimeter of a Rectangle";
}
};
class Second : public First {
public:
int width, height, area, perimeter;
void calculate() {
cout << "Enter Width of Rectangle:";
cin>>width;
cout << "Enter Height of Rectangle:";
cin>>height;
area = height*width;
cout << "Area of Rectangle:" << area;
perimeter = 2 * (height + width);
cout << "\nPerimeter of Rectangle:" << perimeter;
}
};
int main() {
First *f;
Second s;
f = &s;
f->calculate();
return 0;
}
```

#### Output:

```
Enter Width of Rectangle:4
Enter Height of Rectangle:3
Area of Rectangle:12
Perimeter of Rectangle:14
```