Could you tell me why the code for these two readdir loops is different?

The previous paragraph can only get a portion of the file
$han 2 = opendir (' dir ');
while (Readdir ($han 2)!== false) {
Echo Readdir ($han 2);
echo "
";
}
Closedir ($han 2);

This section can get all the documents
$od = Opendir (' dir ');
while (($readd = Readdir ($od))!== false) {
Echo $readd;
echo "
";
}
Closedir ($od);

Reply to discussion (solution)

Readdir returns the file name of the next file in the directory.
Your first piece of code uses only half of the results.

Dir has three files in a B C. The front section while (Readdir ($han 2)!== false) will only move after the cursor is moved to a, and you will be running echo readdir ($han 2) only to read to B. The latter section is used to receive the variable, which can avoid this problem completely.

Readdir returns the file name of the next file in the directory.
Your first piece of code uses only half of the results.

I asked more why the current directory (.) and the top level directory output are displayed when the page is output (..) ）
Which Readdir is the extra feature?

Dir has three files in a B C. The front section while (Readdir ($han 2)!== false) will only move after the cursor is moved to a, and you will be running echo readdir ($han 2) only to read to B. The latter section is used to receive the variable, which can avoid this problem completely.

Thank you.

. And.. It's also a catalog item, and of course it shows up.
If you don't, you have to judge.

Readdir returns the file name of the next file in the directory.
Your first piece of code uses only half of the results.

I asked more why the current directory (.) and the top level directory output are displayed when the page is output (..) ）
Which Readdir is the extra feature?

The PHP kernel is deliberately designed to do so, it may be called C Readdir function, C's Readdir function is also read. Of

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