0.2 Hello World (iteration statements, pointers, make)

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#0.2 Hello World (iteration statements, pointers, make)

hello, world is a classic program that dates back to 1974, first published in
a paper titled Programming in C: A tutorial. The program has one simple
purpose; to print "hello, world".

Since the typical implementation is very trivial, your task is to write a more
versatile alternative, having the following semantics:

$ ./hello
Hello, world!
$ ./hello "DD2387"
Hello, DD2387!
$ ./hello "KTH" 3
Hello, KTH KTH KTH!
$ ./hello "Malcom X" NaN
error: 2nd argument must be an integral greater than zero!
$ ./hello kth dd2387 3
error: Too many arguments!

Note: This assignment is not an exercise in object oriented programming (OOP),
but a mere introduction to the fundamental parts of C++.

0.2.1 Requirements

• The main-function shall be written in a file called main.cpp.

• You shall implement a function which is responsible for printing the hello
  world string, which shall be defined in a separate .cpp file (Translation
  Unit).

• The separate .cpp shall have a corresponding .h-header that contains a
  forward declaration for the function therein. This header is to be#included
  by main.cpp.

• The definition of your print-function shall be compiled seperately, and later
  linked with main.cpp.

• Correct output from your program should be printed through std::cout,
  whereas error diagnostics should be printed through std::cerr.

• The implementation shall pass the tests done by invoking the following
  command:

  /info/DD2387/labs/lab1/0.2_hello_world/hw_verifier

0.2.2 Hints

• Use an argument named argc to main to get the number of arguments passed
  to your application. Remember that the name of the executable counts to this
  number.
• Use an argument named argv to main to get access to the individual
  parameters passed to your application.
• std::atoi from <cstdlib> can be used to convert a char const * to an
  integer. If the function is unable to interpret the data as an integer, it
  will return 0.

0.2.3 Questions

• What is the purpose of std::cout, std::cerr, and std::clog,
  respectively?

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• cout is a stream that prints output to standard output (typically the
  terminal the program is invoked from). It is meant for the main output from a
  program. For instance, a program that copies files might print progress
  information to cout.
• cerr is a stream that prints to standard error (also typically the terminal
  the program is invoked from). It is meant for error output, for instance a
  program that copies files might print warnings and error information such as
  permission issues to cerr.
• clog is meant for log output, and is by default connected to standard
  error. For instance, a program might print fine-grained debugging
  information to clog.

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