Factorial Program in C++

Factorial program in c++

In this C++ program, we are going to determine the factorial of a number using functions. Here I will provide you different ways to find the factorial of a number in c++. First, we use for loop, then functions, and at last recursion.

Factorial program in c++ using for loop.

Source code:

#include<iostream.h>
#include<conio.h>
void main()
{
int num,i;
clrscr();
cout<<"\n Enter a Number:";
cin>>num;
for(i=num-1;i>=1;i--)
num=num*i;
cout<<“\n factorial of a number”;
cout<<“\n entered by you”;
cout<<num;
getch();
}

Output:

Factorial program in c++ using functions

Source code:

#include<iostream.h>
#include<conio.h>
void factorial(int s);
void main()
{
clrscr();
int num;
cout<<"\n Enter a number:";
cin>>num;
factorial(num);
getch();
}
void factorial(int s)
{
int fact=1;
for(int i=s;i>=1;i--)
fact*=i;
cout<<"Factorial of "<<s;
cout<<" is "<<fact;
}

Output:

    Enter a number:6

Factorial of 6 is 720

Factorial program in c++ using recursion 

Source code:

#include<iostream.h>
#include<conio.h>
int factorial(int s);
void main()
{
clrscr();
int num,fact;
cout<<"\n Enter a number:";
cin>>num;
fact=factorial(num);
cout<<"Factorial of "<<num;
cout<<" is "<<fact;
getch();
}
int factorial(int s)
{
int fact_num;
if(s==1)
return(1);
else
fact_num=s*factorial(s-1);
return(fact_num);
}

Output:

Enter a number: 5

Factorial of 5 is 120

Factorial:

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

n! = n*(n-1)*n-2)*…..*1

Algorithm to make a C++ Program to Find Factorial of a Number 

• Let the number given by the user is “n”.
• Now we initialize loop counter with one less than the number given by the user “i= n-1”.
• The testing condition will be that the loop counter should be greater than and equal to 1 “i>=1".
• Now we have to decrease the value of i by one “i=i-1” or “i--".
• for(i=n-1;i>=1;i--)
• We will multiply num by i and stores its value in num.
• num=num*i;
• we have to just print the value of num which will print the factorial of that number entered by the user.

About this blog post:

In this post, I have covered many methods to determine the factorial of a number in c++.

I hope you enjoy this program as much as I enjoy offering this program to you. If you have any questions or queries related to this program, please don't hesitate to comment below.