Factorial of a number in c plus plus

What is a Factorial?

The factorial of a non-negative integer n is the product of all positive integers less than or equal to n.

It is denoted as:
n! = n × (n – 1) × (n – 2) × … × 2 × 1

Examples:

0! = 1 (by definition)
1! = 1
2! = 2 × 1 = 2
3! = 3 × 2 × 1 = 6
4! = 4 × 3 × 2 × 1 = 24
5! = 5 × 4 × 3 × 2 × 1 = 120

using function

#include<iostream>

using namespace std;
int fact(int n)
{
int fact=1;
for(int i=1; i<=n; i++)
{
fact*=i;
}
return fact;
}
int main()
{

cout<<"fact:"<<fact(5)<<endl;

return 0;

}

Iterative Method:

#include<iostream>

using namespace std;

int factorial(int n) {
int result = 1;
for (int i = 2; i <= n; ++i)
result *= i;
return result;
}

int main() {
int num;
cout << “Enter a positive integer: “;

cin >> num;

if (num < 0)
    cout << "Factorial is not defined for negative numbers." << endl;
else
    cout << "Factorial of " << num << " is " << factorial(num) << endl;

return 0;

}

Recursive Method:

include