Factorial program in C++

Factorial program in C++

The product of an integer and all the integers that lies below it is known as the factorial. The Factorial program in C++ is basically a program that is used to display the factorial of an integer that is entered by the user as an input. Please note that the factorial of N is denoted by the N!.

Let's derive the factorial of 5 then it will be:

5! = 5*4*3*2*1 = 120

The most widely use of the factorial generally lies in combination and permutations in mathematics.

Different Ways through which the factorial program in C++ language can be written

There are numerous ways through which one can write the factorial program in C++ language. Here are the two most commonly used ways to write the factorial program as depicted below:

• Factorial Program using loop
• Factorial Program using recursion

1. Factorial Program using Loop

Here is the example

#include <iostream>  
using namespace std;  
int main()  
{  
   int i,f=1,num;    
  cout<<"Please Enter any Number to print factorial : ";    
 cin>>num;    
  for(i=1;i<=num;i++)
  {    
      f=f*i;    
  }    
  cout<<"Here is the Factorial of " <<num<<"  "<<f<<endl;  
  return 0;  
}

2. Factorial Program using Recursion

Here is the example

#include<iostream>    
using namespace std;      
int main()    
{    
int fact(int);    
int f,num;    
cout<<"Enter Your number to print Factorial ";    
cin>>num;    
f=fact(num);    
cout<<"Here is the Factorial of given number : "<<f<<endl;    
return 0;    
}    
int fact(int n)    
{    
	if(n<0)    
	{			
	return(-1); /*if number is less than 0 W*/      
	}
	if(n==0)    
	{
	return(1);  /*if number is 0 then Terminate the  condition*/    
	}
	else    
	{    
	return(n*fact(n-1));        
	}    
}