10 username and password values into parallel arrays

Problem: Write a program that reads 10 username and password values into parallel arrays. After the arrays have been loaded, the program should behave like a login screen, prompting for a username and a password. Based on the data read and stored in the arrays, the program should respond appropriately with one of three output messages: “Username not found.”, “Username and password does not match.” or “Access granted.”
Question 1: Would you write this program asking a user to enter the usernames and passwords or would you use a file that contains all the username and passwords as input? Explain why you would choose one over the other.
Question 2: Will your answer remain the same if the number of username and password values change to 40, and why?