Who can explain in detail the execution process of $ a = 10; $ B = $ a -- + -- $ a; in PHP?

Who can explain in detail the execution process of $ a10; $ B $ a -- + -- $ a; in PHP? When I read Gao luofeng's book "elaborate on PHP", I found {code ...} if the above logic is used, add {code ...} can anyone tell us the detailed execution process of this code? Who can explain in detail the execution process of $ a = 10; $ B = $ a -- + -- $ a; in PHP?

When I read Gao luofeng's book "elaborate on PHP", I found that

$ A = 10; $ B = $ a ++ $ a; // The Execution Process in the book is: $ a First Auto-increment 1 and then auto-increment 1, then assign $ becho $ a; // $ a = 12; echo $ B; // $ B = 22; $ B = $ a ----- $; // $ a first incrementing by 1, then incrementing by 1, and then assigned to $ becho $ a; // $ a = 10 echo $ B; // $ B = 2

If the above logic is used

$b = $a-- + --$a;echo $a;       //$a = 8;echo $b;       //$b = 18;

Can anyone tell us the detailed execution process of this code?

Reply content:

Who can explain in detail the execution process of $ a = 10; $ B = $ a -- + -- $ a; in PHP?

When I read Gao luofeng's book "elaborate on PHP", I found that

$ A = 10; $ B = $ a ++ $ a; // The Execution Process in the book is: $ a First Auto-increment 1 and then auto-increment 1, then assign $ becho $ a; // $ a = 12; echo $ B; // $ B = 22; $ B = $ a ----- $; // $ a first incrementing by 1, then incrementing by 1, and then assigned to $ becho $ a; // $ a = 10 echo $ B; // $ B = 2

If the above logic is used

$b = $a-- + --$a;echo $a;       //$a = 8;echo $b;       //$b = 18;

Can anyone tell us the detailed execution process of this code?

Khan, three sections of code are the same, so it is necessary to put so much? No matter$a++Or++$aYou only need to understand that the code is read from left to right.

$a++It means$aAnd then add 1 to it, so$b = $a++;The output result is$a=11;$b=10;

++$aIs first$aPerform auto-increment 1, and then$aValue, so$b = ++$a;The output result is$a = 11;$b=11;

If you can understand the above two paragraphs, it is not a problem to understand your section based on this idea. Let me talk about your last one:

$b = $a-- + --$a;

This can be split

$c = $a--;$d = --$a;$b = $c + $d;

According to the above explanation,$a--The returned result is$aValue, and then$aAuto-minus 1.$a=9;$c=10;.--$aHere is$aSubtract 1 and then return$aValue, so at this time$a=8;$d=8;. The final result is naturally$a=8;$b=18;.