Write a program that lets a user enter n and that outputs n! (meaning n*(n-1)*(n-2)**2*1). hint: initialize a variable totalvalue to n, and use a loop variable i that counts from n-1 down to 1.

//  This code snippet calculates n! and stores the answer in the variable p.
// Handle 0! = 1 separately.
if (n==0) {
   p = 1;
}
else {
// Initialize p = n
p = n;

// While loop
while (n>1) {
      p = p*(n-1);
      n = n-1;
     }
}