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correct_cpp_is_odd

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Correct C++ chapter 'is odd'.

Goals

• Respond to exceptions

Prerequisites

• Understand how this course works
• Have written a correct 'Show CLI arguments' program

Exercise

Write a command-line interface (CLI) program that determines if its argument is an odd number.

If there are more arguments supplied, ignore the ones beyond the first

With 'Any' output, you can choose to:

• inform the user, for example: 'Error: must supply one argument'
• give no ouput at all: the exit status of 1 indicates that the program ended with an error

This is the code you start with:

main(argc, argv)
{
  //Your code here
}

• Use std::stoi to convert a std::string to an int
• std::stoi properly [2] throws an exception if the std::string cannot be converted to an integer:
  • when the std::string is a word, like nonsense
  • when the std::string is a number too big to be an integer, like 12345678901234567890
• Use try and catch to respond to the exception thrown by std::stoi
• Avoid std::endl [1]
• catch the exception by reference [3]
• You can have multiple catch clauses per try
• Use const to define objects with values that do not change after construction [4]

External links

• Video how to do this chapter (mp4)

References

• [1] C++ Core Guidelines: SL.io.50: Avoid endl
• [2] C++ Core Guidelines: E.2: Throw an exception to signal that a function can't perform its assigned task
• [3] C++ Core Guidelines: E.15: Catch exceptions from a hierarchy by reference
• [4] C++ Core Guidelines: Con.4: Use const to define objects with values that do not change after construction