Java in 21 Days (6th Edition) Day 7: Exceptions and Threads

The cover of Teach Yourself Java in 21 Days (6th Edition) by Rogers Cadenhead

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Notes and Corrections

  • View the Certification Practice quiz solution
  • Certification answer: Answer (c) is correct. The i variable should not be used when calculating the average because it goes up by 1 even when a command-line argument is not a valid floating-point number. For example, if you ran the application like this:

    java AverageTest 1 1 1 x

    The output would be the following:

    Invalid input: x
    Average value: 0.75

    To correct the problem, the statement should be this:

    System.out.println("Average: " + (sum / count));

    Answer (a) is incorrect because the statement works correctly. In the conditional part of a for loop, you can put two expressions together with an & operator or one of the other logical operators.

    Answer (b) is incorrect because the statement works correctly. Each element in the temps[] array is initialized to 0, so if a NumberFormatException is thrown in the for loop, sum += temps[i] will add 0 to the sum.

    Answer (d) is incorrect because there was an error in the application.

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