## C++ to find the factorial of a number using class:

In this post, we will learn how to find the *factorial* of a number using class. *Factorial* of a number is equal to the multiplication of all numbers from *1* to *that number*.

Using a class, we can put all the factorial related operations in the class with a method to calculate the *factorial*. Then, we can create one object of the class and call the *factorial* function of that class to find the factorial.

Using a separate class is helpful to move all related functions in one place. With this program, you will learn how we can create a different class to calculate *factorial*.

### C++ program to calculate factorial using class:

```
#include <iostream>
using namespace std;
class Factorial
{
private:
int num;
int factorial = 1;
public:
void calculateFactorial();
void show();
};
void
Factorial::calculateFactorial()
{
cout << "Enter a number : " << endl;
cin >> num;
if (num == 0 || num == 1)
{
factorial = 1;
}
else
{
while (num > 1)
{
factorial = factorial * num;
num--;
}
}
}
void Factorial::show()
{
cout << "Factorial : " << factorial << endl;
}
int main()
{
Factorial factorial;
factorial.calculateFactorial();
factorial.show();
}
```

#### Explanation:

In this program:

- In this program,
*Factorial*is a class to hold all factorial related functions. *num*and*factorial*are two int variables to hold the number and factorial value.*calculateFactorial*and*show*are two public functions.*calculateFactorial*is used to calculate factorial.*calculateFactorial*reads the user input number and calculates the factorial. It uses one*while loop*to calculate the factorial. It multiplies all numbers from*num*to*1*.*show*is used to show the factorial value, i.e.*factorial*.

### Output:

```
Enter a number :
4
Factorial : 24
Enter a number :
5
Factorial : 120
```