I am a beginner. When I saw the relevant documentation for PHP variables, I personally tested it and it was a little different from the documentation, so I didn’t quite understand it. The document says that the output value under the PHP5 version is 15; but the PHP Chinese website online instance environment is the PHP7 version, so the output value should be 10; but my PHP version is 7, and the output is 15, not 10.
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