The factorial of a positive integer is the multiplication of all positive integer less than or equal to that number.
$$factorial$$ $$of$$ $$number$$ $$n$$ = $$n! = n(n-1)(n-2)...1$$
$$5! = 5\times4\times3\times2\times1 = 120$$
$$4! = 4\times3\times2\times1 = 24$$
In the below example, a recursive function called factorial() is used to calculate factorial of a number.
#include <iostream>
using namespace std;
static int factorial(int);
static int factorial(int x) {
if (x == 0 || x == 1)
{return 1;}
else
{return x*factorial(x-1);}
}
int main(){
cout<<"10! = "<<factorial(10)<<"\n";
cout<<"6! = "<<factorial(6)<<"\n";
return 0;
}
10! = 3628800 6! = 720
The factorial of a number can also be calculated using iterative method.
#include <iostream>
using namespace std;
static int factorial(int);
static int factorial(int x) {
int finalnum = 1;
for(int i = x; i > 0; i--)
{
finalnum = finalnum * i;
}
return finalnum;
}
int main(){
cout<<"10! = "<<factorial(10)<<"\n";
cout<<"6! = "<<factorial(6)<<"\n";
return 0;
}
10! = 3628800 6! = 720
In the below example, the factorial of a number is calculated using ternary operator.
#include <iostream>
using namespace std;
static int factorial(int);
static int factorial(int x) {
int y = (x == 0 || x == 1)? 1 : x*factorial(x-1);
return y;
}
int main(){
cout<<"10! = "<<factorial(10)<<"\n";
cout<<"6! = "<<factorial(6)<<"\n";
return 0;
}
10! = 3628800 6! = 720
