/**
* This program computes the factorial of a number
*/
public class Factorial { // Define a class
public static void main(String[] args) { // The program starts here
int input = Integer.parseInt(args[0]); // Get the user's input
double result = factorial(input); // Compute the factorial
System.out.println(result); // Print out the result
} // The main() method ends here
public static double factorial(int x) { // This method computes x!
if (x < 0) // Check for bad input
return 0.0; // If bad, return 0
double fact = 1.0; // Begin with an initial value
while(x > 1) { // Loop until x equals 1
fact = fact * x; // Multiply by x each time
x = x - 1; // And then decrement x
} // Jump back to start of loop
return fact; // Return the result
} // factorial() ends here
} // The class ends here
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