C++ Program to Find Factorial of a Number

In this tutorial, we will learn about factorial in C++ i.e. how to write a program to find factorial of a number using C++.

Quick Info:💡

↪ Factorial of a number is the product of all the integers from 1 to that number.

↪ For example, the factorial of 4 (denoted by 4!) is 1*2*3*4 i.e. 24. Factorial of a negative number is not defined and the factorial of 0! is 1.

↪ Here, we will find the factorial of a number to display its output on the output console.

Factorial of a number can be performed in two ways:

• Without Recursion
• With Recursion

Factorial of a Number Without Recursion

Factorial of a number without recursion is a simple program to find it.

Simply, the user will be asked to enter a positive integer then, the factorial of a number is computed and displayed to a user.

Example:

#include<iostream.h>
#include<conio.h>
void main(){
int num;
long fact=1;
cout<<"Enter a number:=";
cin>>num;
if(num<0)
cout<<"Factorial of a negative number is not defined";
if(n==0)
cout<<"Factorial of zero is 1";
else
{
while(num>0)
{
fact=fact*num;
num--;
}
cout<<"Factorial:="<<fact;
}
getch();
}

//Output:
Enter a number:=5
Factorial:=120

Working: (Factorial without recursion)

Factorial of a Number With Recursion

Recursion (Recursive function) is defined as – the function calls itself repeatedly unless the code included in the body gets terminated.

Note: Always remember that execution starts from the main body only.

Example:

#include<iostream.h>
#include<conio.h>
int fact(int n)
{
if (n==0)||(n==1)
return 1;
else
return fact(n-1)*n;
}
void main(){
int n;
cout<<"enter a positive integer:=";
cin>>n;
cout<<"Factorial is:="<<fact(n);
getch();
}

//Output:
enter a positive integer:=4
Factorial is:=24

Working: (Factorial with Recursion)

Note: Due to recursion, for each function call, an entry is first created in the stack frame and are then executed in a LIFO manner(i.e. Last In First Out).

Want more programs on recursion?

Just Visit: Fibonacci,

Well, I hope it really helped you to know C++ better.

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