Factorial Program

#include <stdio.h>
int main() {
int num=7, i;
unsigned long long fact = 1;
if (num < 0)
printf("Error! Factorial of a negative number doesn't exist.");
else {
for (i = 1; i <= num; ++i) {
fact *= i;
}
printf("Factorial of %d = %llu", num, fact);
}
return 0;
}

#include <iostream>
using namespace std;
int main()
{
unsigned int num=7;
unsigned long long factorial = 1;
for(int i = 1; i <=num; ++i)
{
factorial *= i;
}
cout << "Factorial of " << num << " = " << factorial;    
return 0;
}

public class LFC {
public static void main(String[] args) {
int num = 7;
long factorial = 1;
for(int i = 1; i <= num; ++i)
{
// factorial = factorial * i;
factorial *= i;
}
System.out.printf("Factorial of %d = %d", num, factorial);
}
}

num = 7
# To take input from the user
#num = int(input("Enter a number: "))
factorial = 1
# check if the number is negative, positive or zero
if num < 0:
print("Error, factorial does not exist for negative numbers")
elif num == 0:
print("The factorial of 0 is 1")
else:
for i in range(1,num + 1):
factorial = factorial*i
print("Factorial of",num,"=",factorial)

using System;  
public class LFC  
{  
public static void Main(string[] args)  
{  
int i,fact=1,num=7;      
for(i=1;i<=num;i++){      
fact=fact*i;      
}      
Console.Write("Factorial of " +num+" = "+fact);    
}  
}  

$num = 7;  
$fact = 1;  
for ($x=$num; $x>=1; $x--)   
{  
$fact = $fact * $x;  
}  
echo "Factorial of $num = $fact";