How can quadratic-equation inputs be provided as command-line arguments?

"This program was interactive. As an alternative, we could have read all three of the inputs as command line arguments, converting them to floating point numbers. Lines 12–17 in the program could have been changed to a = atof(argv[1]); b = atof(argv[2]); c = atof(argv[3]); Finally, think about the possible inputs a user could provide that may cause problems for this program. For example: What if the user entered zero for a? What if the user entered some combination such that b^2 < 4ac? What if the user entered non-numeric values? For the command line argument version, what if the user provided less than three arguments? Or more? How might we prevent the consequences of such bad inputs? How might we handle the event that a user enters bad input and how do we communicate these errors to the user? To begin to resolve these issues, we’ll need conditionals."