<HTML ><HEAD ><TITLE >Incrementing/Decrementing Operators</TITLE ><META NAME="GENERATOR" CONTENT="Modular DocBook HTML Stylesheet Version 1.44"><LINK REL="HOME" TITLE="PHP Manual" HREF="manual.html"><LINK REL="UP" TITLE="Operators" HREF="language.operators.html"><LINK REL="PREVIOUS" TITLE="Execution Operators" HREF="language.operators.execution.html"><LINK REL="NEXT" TITLE="Logical Operators" HREF="language.operators.logical.html"></HEAD ><BODY BGCOLOR="#FFFFFF" TEXT="#000000" LINK="#0000FF" VLINK="#840084" ALINK="#0000FF" ><DIV CLASS="NAVHEADER" ><TABLE WIDTH="100%" BORDER="0" CELLPADDING="0" CELLSPACING="0" ><TR ><TH COLSPAN="3" ALIGN="center" >PHP Manual</TH ></TR ><TR ><TD WIDTH="10%" ALIGN="left" VALIGN="bottom" ><A HREF="language.operators.execution.html" >Prev</A ></TD ><TD WIDTH="80%" ALIGN="center" VALIGN="bottom" >Chapter 10. Operators</TD ><TD WIDTH="10%" ALIGN="right" VALIGN="bottom" ><A HREF="language.operators.logical.html" >Next</A ></TD ></TR ></TABLE ><HR ALIGN="LEFT" WIDTH="100%"></DIV ><DIV CLASS="sect1" ><H1 CLASS="sect1" ><A NAME="language.operators.increment" >Incrementing/Decrementing Operators</A ></H1 ><P > PHP supports C-style pre- and post-increment and decrement operators. </P ><DIV CLASS="table" ><P ><B >Table 10-4. Increment/decrement Operators</B ></P ><TABLE BORDER="1" CLASS="CALSTABLE" ><TR ><TH ALIGN="LEFT" VALIGN="MIDDLE" >example</TH ><TH ALIGN="LEFT" VALIGN="MIDDLE" >name</TH ><TH ALIGN="LEFT" VALIGN="MIDDLE" >effect</TH ></TR ><TR ><TD ALIGN="LEFT" VALIGN="MIDDLE" >++$a</TD ><TD ALIGN="LEFT" VALIGN="MIDDLE" >Pre-increment</TD ><TD ALIGN="LEFT" VALIGN="MIDDLE" >Increments $a by one, then returns $a.</TD ></TR ><TR ><TD ALIGN="LEFT" VALIGN="MIDDLE" >$a++</TD ><TD ALIGN="LEFT" VALIGN="MIDDLE" >Post-increment</TD ><TD ALIGN="LEFT" VALIGN="MIDDLE" >Returns $a, then increments $a by one.</TD ></TR ><TR ><TD ALIGN="LEFT" VALIGN="MIDDLE" >--$a</TD ><TD ALIGN="LEFT" VALIGN="MIDDLE" >Pre-decrement</TD ><TD ALIGN="LEFT" VALIGN="MIDDLE" >Decrements $a by one, then returns $a.</TD ></TR ><TR ><TD ALIGN="LEFT" VALIGN="MIDDLE" >$a--</TD ><TD ALIGN="LEFT" VALIGN="MIDDLE" >Post-decrement</TD ><TD ALIGN="LEFT" VALIGN="MIDDLE" >Returns $a, then decrements $a by one.</TD ></TR ></TABLE ></DIV ><P > Here's a simple example script: <DIV CLASS="informalexample" ><P ></P ><TABLE BORDER="0" BGCOLOR="#E0E0E0" WIDTH="100%" ><TR ><TD ><PRE CLASS="programlisting" > 1 2 <?php 3 echo "<h3>Postincrement</h3>"; 4 $a = 5; 5 echo "Should be 5: " . $a++ . "<br>\n"; 6 echo "Should be 6: " . $a . "<br>\n"; 7 8 echo "<h3>Preincrement</h3>"; 9 $a = 5; 10 echo "Should be 6: " . ++$a . "<br>\n"; 11 echo "Should be 6: " . $a . "<br>\n"; 12 13 echo "<h3>Postdecrement</h3>"; 14 $a = 5; 15 echo "Should be 5: " . $a-- . "<br>\n"; 16 echo "Should be 4: " . $a . "<br>\n"; 17 18 echo "<h3>Predecrement</h3>"; 19 $a = 5; 20 echo "Should be 4: " . --$a . "<br>\n"; 21 echo "Should be 4: " . $a . "<br>\n"; 22 ?> 23 </PRE ></TD ></TR ></TABLE ><P ></P ></DIV > </P ></DIV ><DIV CLASS="NAVFOOTER" ><HR ALIGN="LEFT" WIDTH="100%"><TABLE WIDTH="100%" BORDER="0" CELLPADDING="0" CELLSPACING="0" ><TR ><TD WIDTH="33%" ALIGN="left" VALIGN="top" ><A HREF="language.operators.execution.html" >Prev</A ></TD ><TD WIDTH="34%" ALIGN="center" VALIGN="top" ><A HREF="manual.html" >Home</A ></TD ><TD WIDTH="33%" ALIGN="right" VALIGN="top" ><A HREF="language.operators.logical.html" >Next</A ></TD ></TR ><TR ><TD WIDTH="33%" ALIGN="left" VALIGN="top" >Execution Operators</TD ><TD WIDTH="34%" ALIGN="center" VALIGN="top" ><A HREF="language.operators.html" >Up</A ></TD ><TD WIDTH="33%" ALIGN="right" VALIGN="top" >Logical Operators</TD ></TR ></TABLE ></DIV ></BODY ></HTML >
