1. The program starts by printing your name with an end sign ">". For ex, "FirstName LastName >";

2. No matter what an input line is, the program print: "Do you want to use my vi to edit a file: test.txt? Y or N";

3. If "Y" or "y",
a) print out "OK, I've made a copy of your file at: test1.txt";
b) your program will open "test.txt" for reading, and open "test1.txt" for writing;
c) prepare a head line into "test1.txt" saying that "The following is a copy from test.txt";
d) copy the contents from "test.txt" to "test1.txt", and your program exit.

4. If "N" or "n", print out "OK. I will work on a vi system.", and your program exit;

5. If otherwise, print out "Error.", and your program go to Step 2.

Here are some other requirements:
1. You should use functions, for ex, one for checking the input and another for handling the two files;
2. You should have comments which describe what the functions do;
3. Each function cannot be over 100 lines of code except the main function.