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Find Factorial of a Number in C++ With and Without Recursion

To find factorial of a number in C++ Programming a common question in practical exams. Not only in C++, but also in C, Java, VB, C#, Python, etc.

What is factorial of a number?

Factorial of a number is the product of numbers from 1 to that number.

For example:

If we want to find factorial of 5,
Then it should be : 1 x 2 x 3 x 4 x 5 = 120.
Like this factorial of 4 should be 24. ( 1 x 2 x 3 x 4 = 24).
In computer, we use * symbol instead of multiplication symbol (x).

C++ Program to find Factorial of a Number

Here we find factorial of a given number using for loop, which starts from 1 till to given number. Variable ‘fact’ gets multiplication products from 1 to that number.

#include <iostream>
using namespace std;

int main()
{
    int num, fact = 1;
    cout << "Type a number : " ;
    cin>>num;
    for(int i=1;i<=num;i++)
    {
     fact = fact * i;
    }
    cout<<"Factorial of " << num << " is : "<< fact;
    return 0;
}

Using While Loop

#include <iostream>
using namespace std;

int main()
{
    int num, fact = 1, i=1;
    cout << "Type a number : " ;
    cin>> num;
    while(i <= num)
    {
     fact = fact * i;
     i++;
    }
    cout<< "Factorial of " << num << " is : "<< fact;
    return 0;
}

Find Factorial using Recursion

Recursion is the calling a function from it’s function body.
Here is a function named factorial and inside it’s body, program call again same function name(factorial) again.

#include <iostream>
using namespace std;
int factorial(int);

int main()
{
    int num;
    cout << "Type a number : " ;
    cin>>num;
    cout<<"Factorial of " << num << " is : "<< factorial(num);
    return 0;
}
int factorial(int num)
{
    if(num == 1)
        return 1;
    else
     {
        return(num * factorial(num-1));
     }

}

Sample Output:

Factorial of a number in C++

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