“Hello, World” and friends.

exercise No. 1

Starting from and extending class Hello

Q:

  1. Fire up you IntelliJ Idea development environment and create the following class Hello: 

    void main() {
   IO.println("Hello, World ...");
}

  2. Run the class and observe the output.

  3. Extend your current code to produce multiple output lines: 

    Those who can do.
Those, who cannot, teach.
Those, who cannot teach, lecture trainee teachers teaching methodology.

A:

There are several options for creating a whole paragraph spanning multiple text lines:

  1. Using Java 13 multiline string literals (best): 

    void main() {
  IO.println("""
     Those who can do.
     Those, who cannot, teach.
     Those, who cannot teach, lecture trainee teachers teaching methodology.""" );
}

  2. Straightforward: Using multiple println(...) statements: 

    void main() {
   IO.println("Those who can do.");
   IO.println("Those, who cannot, teach.");
   IO.println("Those who cannot teach lecture trainee teachers teaching methodology.");
}

  3. Long strings exceeding your editor's desired maximum line length may be decomposed into smaller chunks using the “+” ❶ string concatenation operator: 

    void main() {
  IO.println(
    "Those who can do.\n"  + ❶
    "Those, who cannot, teach.\n"  +
    "Those, who cannot teach, " +
    "lecture trainee teachers teaching methodology."); // No \n at end, println(...) does it.
}

    Note

    »\n« represents the newline character. Without it the three sentences would be concatenated into a single line of text.

    The IO.println(...) method adds a final line break to the content in question.

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