I need help with this c++ assignment question (most important is c, but if you can help with all please do), please use loops if possible as I think this is an assignment on loops, however I could be wrong. I am using visual studio.

The factorial of a positive integer n is written n! and is defined as follows: n! = n* (n-1* (n-2)* ....* 1 for values of n greater than 1 and n! = 1 for n = 0 or n = 1. a) Write a program that reads a positive integer and computes and prints its factorial. b) Write a program that estimates the value of the mathematical constant e by using the formula: e = 1 + 1/1! + 1/2!+ 1/3! + .... Prompt the user for the desired accuracy of e (the number of terms in the summation). c) Write a program that computes the value of e* by using the formula ex = 1 + x/1! + x2/2! + x3/3! + ... Prompt the user for the desired accuracy of e ( the number of terms in the summation)