六六の魔法世界

//if....else if.....else;
int $number = 27;
if ($number < 23)
{
    print ($number + "is less than twenty-three.\n");
}
else if ($number < 25)
{
    print ($number + "is less than twenty-five.\n");
}
else if ($number == 25)
{
    print ($number + "is equal to twenty-five.\n");
}
else
{
    print ($number + "is greater than twenty-five.\n");
}
//嵌套式if语句（注意缩进）；
if ($number < 30)
{
    if ($number < 20)
    {
        print ("It's less than 20!\n");
        if ($number == 13)
        {
            print("It's 13!\n");
        }
    }
    else{
        print("Hmm,I think it's between 20 and 30?\n");
    }

}
//
int $test = 23;
if($test)
{
    print "I'm not zero!\n";
}
//
$test = 0;
if($test)
{
    print "I'm not zero!\n";
}
//"非"运算符；
$test = 0;
if(! $test)
{
    print "I'm zero!\n";
}
//"与"运算符；
if((3<4) && (3<5))
{
    print "Both are true\n";
}
//"或"运算符；
if((3<4) || (3>5))
{
    print "Either or both are true\n";
}