Consider the following sequence:

\(\Big\{\begin{array}{c} U_0=1 \\ U_n=U_{n-1}+\frac{U_{n-1}}{n!} \texttt{ if } n>0\end{array}\)

1. Write the function int Factorial (int n) that returns the factorial of an integer n.
2. Write the function float Sequence(int n) that returns the value of U_n defined in the above sequence and uses the function Factorial.
3. Write a main function that asks the user to enter an integer n, calculates and prints the value of U_n.

#include<stdio.h>

int factorial(int n)
{
	int i, fact=1;
	for(i=2; i<=n;i++)
		fact*=i;
	return fact;
}

float sequence(int n)
{
	int i;
	float u0=1, u1;
	for(i=1; i<=n;i++)
	{
		u1=u0+u0/factorial(i);
		u0=u1;
	}
	return u1;
}

void main()
{
	int n;
	do{
		printf("Enter n: ");
		scanf("%d", &n);
	}while(n<0);

	printf("Un=%f\n",sequence(n));
}