Does `input.Scan()` Require an `if`-Clause to Handle 'end' Input?

Linda Hamilton
Release: 2024-11-11 21:57:03
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Does `input.Scan()` Require an `if`-Clause to Handle

Breaking Out of input.Scan() without an if-Clause

In your code, you seek to eliminate the if-clause that handles the "end" input. Let's examine the documentation of input.Scan() to clarify if an if-clause is necessary.

According to the documentation, input.Scan() advances to the next token and returns false when the scan ends either due to reaching the end of the input or an error. However, the default split function for input.Scan() is ScanLines, which returns each line of text without any trailing end-of-line markers.

Two crucial points to note here are:

  1. ScanLines handles empty lines: It means it returns empty lines as tokens.
  2. Last non-empty line is returned without a newline: If the last line of input is non-empty, it will be returned even if it lacks a newline.

Therefore, typing an empty line (pressing Enter) will not end the scanner. It will merely return an empty line as a token. The scanner will only stop running when:

  • End-of-File (EOF) is reached: This can be achieved by typing Ctrl-D or using another method to signal the end of input.
  • An error occurs while scanning: This is unlikely in basic scenarios.

Based on this understanding, it is unnecessary to include an if-clause to check for empty input. The scanner will break out of the loop automatically when EOF is reached.

To summarize, your code will continue to work as intended, breaking out of the loop when the user types "end" or reaches EOF, even without the if-clause.

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