$d = getdate(mktime(1,1,1,$m,1,$y)); //the first of the month
$ff = (5 - $d["wday"] +7)%7+1; //the first friday
| Possible day of week that first of month could fall on |
$d["wday"] |
5-$d["wday"] See negative value |
5 - $d["wday"] +7 |
(5 - $d["wday"] +7)%7 |
(5 - $d["wday"] +7)%7+1 |
| Sunday | 0 | 5 | 12 | 5 | 6 |
| Monday | 1 | 4 | 11 | 4 | 5 |
| Tuesday | 2 | 3 | 10 | 3 | 4 |
| Wednesday | 3 | 2 | 9 | 2 | 3 |
| Thursday | 4 | 1 | 8 | 1 | 2 |
| Friday | 5 | 0 | 7 | 0 | 1 |
| Saturday | 6 | -1 | 6 | 6 | 7 |
It could be done with a switch
switch ($d["wday"]) {
case 0:
//first is Sunday
$ff=6;
break;
case 1:
//first is Monday
$ff=5;
break;
case 2:
//first is Tuesday
$ff=4;
break;
case 3:
//first is Wednesday
$ff=3;
break;
case 4:
//first is Thursday
$ff=2;
break;
case 5:
//first is Friday
$ff=1;
break;
case 6:
//first is Saturday
$ff=7;
break;
default:
//code to be executed if n is different from all labels;
}