Pset 2( 2 Questions) Caesar

Question

it is about pset 2 caesar.c

Question 1: Do I need to consider the case when the user input something after ./caesar (argv [1]) instead of an integer?

Example: ./ caesar a

Question 2: I found out the following hints from the cs50 website:

$ ./caesar Usage: ./caesar k $ ./caesar 1 2 3 4 5 Usage: ./caesar k

Is that mean I have to printf("Usage: ./caesar k\n") and to return 0; when argc equal to 2?

Answer 1

1. Quoting the problem specification:

   • You can assume that, if a user does provide a command-line argument, it will be a non-negative integer (e.g., 1). No need to check that it’s indeed numeric.

2. Same source:

   • If your program is executed without any command-line arguments or with more than one command-line argument, your program should print an error message of your choice (with printf) and return from main a value of 1 (which tends to signify an error) immediately.