Input Verification

Let's return to the problem that introduced this lesson and consider how to use a while loop to enforce input constraints. Take a look at ``examples/kelvin.c''. You can also view it directly.

Study the program, run it a few times, and then try to answer the following questions.

  1. Why do we set the value of temp to -1 before the loop?
  2. If the loop condition is initially true, what makes it eventually change and become false so the loop can stop?
  3. What will happen if the user refuses to enter a positive number?
  4. How can we be confident that the final value of temp will be positive?

Click here for the answers

Before we move along, try to write a function of no arguments that prompts the user for and returns a positive temperature in degrees Kelvin. In other words, package up the program that we just wrote as a function.

Click here for the answer

Joseph L. Zachary
Hamlet Project
Department of Computer Science
University of Utah