**Factorial of a number using class**

**Factorial of a number using class**

Write a C++ Program to find Factorial of a number using class. Here’s simple C++ Program to find Factorial of a number using class in C++ Programming Language.

*What are Functions ?*

*What are Functions ?*

Function is a block of statements that performs some operations. All C++ programs have at least one function – function called “main()”. This function is entry-point of your program.

A function **declaration** tells the compiler about a function’s name, return type, and parameters. A function **definition** provides the actual body of the function.

**Defining a Function : :**

**Defining a Function : :**

The general form of a C++ function definition is as follows:

return_type Function_Name( list of parameters )

{

//function’s body

}

**return_type :**suggests what the function will return. It can be void, int, char, some pointer or even a class object.**Function_Name :**is the name of the function, using the function name it is called.**Parameters :**are variables to hold values of arguments passed while function is called. A function may or may not contain parameter list.**Function body :**is he part where the code statements are written.

Below is the source code for C++ Program to find Factorial of a number using class which is successfully compiled and run on Windows System to produce desired output as shown below :

**SOURCE CODE : :**

**SOURCE CODE : :**

/* C++ Program to find Factorial of a number using class */ #include<iostream> using namespace std; class factorial { private: int n,n1,f=1; public: void input(); void calc(); void display(); }; void factorial::input() { cout<<"\nEnter any number :: "; cin>>n; } void factorial::calc() { n1=n; if(n==0||n==1) cout<<"\nFactorial of Number [ "<<n<<" ] is :: 1\n"; else { while(n>0) { f=f*n; n--; } } } void factorial::display() { cout<<"\nFactorial of [ "<<n1<<" ] is :: "<<f<<"\n"; } int main () { factorial f; f.input(); f.calc(); f.display(); return 0; }

**OUTPUT : :**

**OUTPUT : :**

/* C++ Program to find Factorial of a number using class */ Enter any number :: 6 Factorial of [ 6 ] is :: 720 Process returned 0

Above is the source code for C++ Program to find Factorial of a number using class which is successfully compiled and run on Windows System.The Output of the program is shown above .

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It would seem this program works without (n==0||n==1) and a condition of (n<0) is missing, no?

then it always so 1

we can calculate by using while( n>0) we donot need to include n==1 and n==0