Iterative solution for factorial of a number

Factorial can be evaluated recursively and its very difficult for large numbers. So here we writing code in recursive way using for loop and while loop.

Using For Loop:

C++ program for factorial of a number

// C++ program for factorial of a number
#include <iostream>
using namespace std;

// function to find factorial of given number
unsigned int factorial(unsigned int n)
{
	int res = 1, i;
	for (i = 2; i <= n; i++)
		res *= i;
	return res;
}

// Driver code
int main()
{
	int num = 5;
	cout << "Factorial of "
		<< num << " is "
		<< factorial(num) << endl;
	return 0;
}

// This code is contributed by Shivi_Aggarwal

C program for factorial of a number

#include <stdio.h>

// function to find factorial of given number
unsigned int factorial(unsigned int n)
{
	int res = 1, i;
	for (i = 2; i <= n; i++)
		res *= i;
	return res;
}

int main()
{
	int num = 5;
	printf(
		"Factorial of %d is %d", num, factorial(num));
	return 0;
}

Java program for factorial of a number

// Java program to find factorial of given number
class Test {
	// Method to find factorial of the given number
	static int factorial(int n)
	{
		int res = 1, i;
		for (i = 2; i <= n; i++)
			res *= i;
		return res;
	}

	// Driver method
	public static void main(String[] args)
	{
		int num = 5;
		System.out.println(
			"Factorial of " + num
			+ " is " + factorial(5));
	}
}

Python 3 program for factorial of a number

# Python 3 program to find
# factorial of given number

# Function to find factorial of given number
def factorial(n):
	
	res = 1
	
	for i in range(2, n+1):
		res *= i
	return res

# Driver Code
num = 5;
print("Factorial of", num, "is",
factorial(num))

# This code is contributed by Smitha Dinesh Semwal

C# program for factorial of a number

// C# program to find
// factorial of given number
using System;

class Test {
	// Method to find factorial
	// of given number
	static int factorial(int n)
	{
		int res = 1, i;

		for (i = 2; i <= n; i++)
			res *= i;
		return res;
	}

	// Driver method
	public static void Main()
	{
		int num = 5;
		Console.WriteLine(
			"Factorial of " + num
			+ " is " + factorial(5));
	}
}

// This code is contributed by vt_m

PHP program for factorial of a number

<?php

// function to find factorial
// of given number
function factorial( $n)
{
	$res = 1; $i;
	for ($i = 2; $i <= $n; $i++)
		$res *= $i;
	return $res;
}

// Driver Code
$num = 5;
echo "Factorial of ", $num, " is ",
					factorial($num);

// This code is contributed
// by anuj_67.
?>

Output :

Factorial of 5 is 120

Using While Loop:

C Program for factorial of a number

// C program for factorial of a number
#include <stdio.h>

// function to find factorial of given number
unsigned int factorial(unsigned int n)
{
	if(n == 0)
		return 1;
	int i = n, fact = 1;
	while (n / i != n) {
		fact = fact * i;
		i--;
	}
	return fact;
}

int main()
{
	int num = 5;
	printf("Factorial of %d is %d", num, factorial(num));
	return 0;
}

C++ Program for factorial of a number

// C++ program for factorial of a number
#include <iostream>
using namespace std;

// function to find factorial of given
// number using while loop
unsigned int factorial(unsigned int n)
{
	if(n == 0)
		return 1;
	int i = n, fact = 1;
	while (n / i != n) {
		fact = fact * i;
		i--;
	}
	return fact;
}

// Driver code
int main()
{
	int num = 5;
	cout << "Factorial of "
		<< num << " is "
		<< factorial(num) << endl;
	return 0;
}
// This code is contributed by Shivi_Aggarwal

Java Program for factorial of a number

// Java program to find factorial of given number
class Test {
	// Method to find factorial of the given number
	static int factorial(int n)
	{
		if(n == 0)
		return 1;
		int i = n, fact = 1;
		while (n / i != n) {
			fact = fact * i;
			i--;
		}
		return fact;
	}

	// Driver method
	public static void main(String[] args)
	{
		int num = 5;
		System.out.println(
			"Factorial of " + num
			+ " is " + factorial(5));
	}
}

Python Program for factorial of a number

# Python 3 program to find
# factorial of given number

# Function to find factorial of given number
def factorial(n):
	if(n == 0):
	return 1
	i = n
	fact = 1
	
	while(n / i != n):
		fact = fact * i
		i -= 1
		
	return fact

# Driver Code
num = 5;
print("Factorial of", num, "is",
factorial(num))

# This code is contributed by Smitha Dinesh Semwal

C# Program for factorial of a number

// C# program to find
// factorial of given number
using System;

class Test {
	// Method to find factorial
	// of given number
	static int factorial(int n)
	{
		if(n == 0)
			return 1;
		int i = n, fact = 1;
		while (n / i != n) {
			fact = fact * i;
			i--;
		}
		return fact;
	}

	// Driver method
	public static void Main()
	{
		int num = 5;
		Console.WriteLine(
			"Factorial of " + num
			+ " is " + factorial(5));
	}
}

Output:

Factorial of 5 is 120

So time complexity of above iterative is O(n).

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Lingaraj Senapati
Hey There! I am Lingaraj Senapati, the Co-founder of lingarajtechhub.com My skills are Freelance, Web Developer & Designer, Corporate Trainer, Digital Marketer & Youtuber.
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