PHP运算符

$a = 13;
echo $a % 3;//1
echo "
";
$a = -13;
echo $a % 3;//-1

$a = 1;
$b = 2;
$c = $a++ + ++$a + ++$b;
$d = $a++ - $c-- + $b++;
//a 4
//b 4
//c 1+2+3=7
//d 3-7+3=-1

$a = 5;
$b = 4;
$c = $b++ + ++$a - $b++;
$d = $c++ + $b++ - $a--;
echo $a;//5
echo "
";
echo $b;//7
echo "
";
echo $c;//4+6-4=6
echo "
";
echo $d;//5

    $url = "http://www.baidu.com";
    echo "百度";
    echo '百度';

$a =10;
$b = 5;
if($a = 8 || $b = 7){
    $b++;
}
echo $a;//1
echo "
";
echo $b;//6

$a =10;
$b = 5;
if($a = 8 && $b = 7){
    $b++;
}
echo $a;//1
echo "
";
echo $b;//8