这个没有深入。

     ';        }        return $sum;    }    addNumbers(1, 2, true);    echo "
";    addNumbers(10, 34, true);    echo "
";    addNumbers(1, 46, true);    $bookJson = file_get_contents('books.json');    $books = json_decode($bookJson, true);    foreach ($books as $key => $book) {        foreach ($book as $bookKey => $bookItem) {            echo $key . '. ' . $bookKey . '->' . $bookItem . '
';        }            }?>

books.json

[    {        "title": "To Kill A Mockingbird",        "author": "Harper Lee",        "available": true,        "pages": 336,        "isbn": 9780061120084    },    {        "title": "1984",        "author": "George Orwell",        "available": true,        "pages": 267,        "isbn": 9780547249643    },    {        "title": "One Hundred Years Of Solitude",        "author": "Gabriel Garcia Marquez",        "available": false,        "pages": 457,        "isbn": 9785267006323    }]

输出：

The sum is 3The sum is 44The sum is 470. title->To Kill A Mockingbird0. author->Harper Lee0. available->10. pages->3360. isbn->97800611200841. title->19841. author->George Orwell1. available->11. pages->2671. isbn->97805472496432. title->One Hundred Years Of Solitude2. author->Gabriel Garcia Marquez2. available->2. pages->4572. isbn->9785267006323