Looking for the answer to the double loop operation of for, the effect is like this

Question

Answer 1

<?php

//The following is a double-layer for, you should be able to understand it

echo '<table width="800" border="1">' ;

$m=0;

for($i=0; $i <10 ; $i++){

for($y=0;$y< ;10;$y++){

echo '<td>'.$m.'</td>';

$m++;

}

if($i%2==0){

echo '<tr bgcolor="red">';

}

else echo '</tr>'; }

echo "</table>";

?>

##

Answer 2

<?php
//循环
for($i='0';$i<'10';$i++){
	for($j='0';$j<'10';$j++){
		echo $j+'10'*$i;
	}
	echo '<br/>';
}