6.6. Incrementing and Decrementing OperatorsThe next two operators do different things, depending on where you place them. The difference is explained in Table 6-6.
The incrementing and decrementing operators can be placed either before or after a variable, and the effect is different depending on where the operator is placed. Here's a code example: $foo = 5; $bar = $foo++; print "Foo is $foo\n"; print "Bar is $bar\n"; That will output the following: Foo is 6 Bar is 5 The reason behind this is that ++, when placed after a variable, is the post-increment operator, which immediately returns the original value of the variable before incrementing it. In line 2 of our script, the value of $foo (5) is returned and stored in $bar, then $foo is incremented by one. If we had put the ++ before $foo rather than after it, $foo would have been incremented then returned, which would have made both $foo and $bar 6. |