I have an assignment due soon and I have no idea where to start and what to do. This is the assignment as written by my teacher:

Write a program that reads two positive integers that are 20 or fewer digits in length and then ouputs their sum. Your program will read the digits as values of type char so that the number 1234 is read in as the four characters '1', '2', '3', '4'. After they are read into the program that characters are changed to values of type int. The digits will be read into a partially filled array, and you might find it useful to reverse the order of the elments in the array ater the data is read. Perform the addition by implementing hte usual pencil-and-paper algorithm. The result of the addition is stored in an array the same size as the input arrays and the result is written to the screen. If the result of the addition is an iteger with more than the maximum number of digits, the program should print a message saying it has encountered "integer overflow".

My teacher did not teach us much about arrays and I am so lost. any help on any oft he points in this problem would be really reaqlly apreciated!