<!DOCTYPE html PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN" "http://www.w3.org/TR/html4/loose.dtd"> <html> <!-- Created by GNU Texinfo 6.5, http://www.gnu.org/software/texinfo/ --> <head> <meta http-equiv="Content-Type" content="text/html; charset=utf-8"> <title>Increment Ops (GNU Octave (version 5.1.0))</title> <meta name="description" content="Increment Ops (GNU Octave (version 5.1.0))"> <meta name="keywords" content="Increment Ops (GNU Octave (version 5.1.0))"> <meta name="resource-type" content="document"> <meta name="distribution" content="global"> <meta name="Generator" content="makeinfo"> <link href="index.html#Top" rel="start" title="Top"> <link href="Concept-Index.html#Concept-Index" rel="index" title="Concept Index"> <link href="index.html#SEC_Contents" rel="contents" title="Table of Contents"> <link href="Expressions.html#Expressions" rel="up" title="Expressions"> <link href="Operator-Precedence.html#Operator-Precedence" rel="next" title="Operator Precedence"> <link href="Assignment-Ops.html#Assignment-Ops" rel="prev" title="Assignment Ops"> <style type="text/css"> <!-- a.summary-letter {text-decoration: none} blockquote.indentedblock {margin-right: 0em} blockquote.smallindentedblock {margin-right: 0em; font-size: smaller} blockquote.smallquotation {font-size: smaller} div.display {margin-left: 3.2em} div.example {margin-left: 3.2em} div.lisp {margin-left: 3.2em} div.smalldisplay {margin-left: 3.2em} div.smallexample {margin-left: 3.2em} div.smalllisp {margin-left: 3.2em} kbd {font-style: oblique} pre.display {font-family: inherit} pre.format {font-family: inherit} pre.menu-comment {font-family: serif} pre.menu-preformatted {font-family: serif} pre.smalldisplay {font-family: inherit; font-size: smaller} pre.smallexample {font-size: smaller} pre.smallformat {font-family: inherit; font-size: smaller} pre.smalllisp {font-size: smaller} span.nolinebreak {white-space: nowrap} span.roman {font-family: initial; font-weight: normal} span.sansserif {font-family: sans-serif; font-weight: normal} ul.no-bullet {list-style: none} --> </style> <link rel="stylesheet" type="text/css" href="octave.css"> </head> <body lang="en"> <a name="Increment-Ops"></a> <div class="header"> <p> Next: <a href="Operator-Precedence.html#Operator-Precedence" accesskey="n" rel="next">Operator Precedence</a>, Previous: <a href="Assignment-Ops.html#Assignment-Ops" accesskey="p" rel="prev">Assignment Ops</a>, Up: <a href="Expressions.html#Expressions" accesskey="u" rel="up">Expressions</a> [<a href="index.html#SEC_Contents" title="Table of contents" rel="contents">Contents</a>][<a href="Concept-Index.html#Concept-Index" title="Index" rel="index">Index</a>]</p> </div> <hr> <a name="Increment-Operators"></a> <h3 class="section">8.7 Increment Operators</h3> <p><em>Increment operators</em> increase or decrease the value of a variable by 1. The operator to increment a variable is written as ‘<samp>++</samp>’. It may be used to increment a variable either before or after taking its value. </p> <p>For example, to pre-increment the variable <var>x</var>, you would write <code>++<var>x</var></code>. This would add one to <var>x</var> and then return the new value of <var>x</var> as the result of the expression. It is exactly the same as the expression <code><var>x</var> = <var>x</var> + 1</code>. </p> <p>To post-increment a variable <var>x</var>, you would write <code><var>x</var>++</code>. This adds one to the variable <var>x</var>, but returns the value that <var>x</var> had prior to incrementing it. For example, if <var>x</var> is equal to 2, the result of the expression <code><var>x</var>++</code> is 2, and the new value of <var>x</var> is 3. </p> <p>For matrix and vector arguments, the increment and decrement operators work on each element of the operand. </p> <p>Here is a list of all the increment and decrement expressions. </p> <dl compact="compact"> <dt><code>++<var>x</var></code></dt> <dd><a name="index-_002b_002b"></a> <p>This expression increments the variable <var>x</var>. The value of the expression is the <em>new</em> value of <var>x</var>. It is equivalent to the expression <code><var>x</var> = <var>x</var> + 1</code>. </p> </dd> <dt><code>--<var>x</var></code></dt> <dd><a name="index-_002d_002d"></a> <p>This expression decrements the variable <var>x</var>. The value of the expression is the <em>new</em> value of <var>x</var>. It is equivalent to the expression <code><var>x</var> = <var>x</var> - 1</code>. </p> </dd> <dt><code><var>x</var>++</code></dt> <dd><a name="index-_002b_002b-1"></a> <p>This expression causes the variable <var>x</var> to be incremented. The value of the expression is the <em>old</em> value of <var>x</var>. </p> </dd> <dt><code><var>x</var>--</code></dt> <dd><a name="index-_002d_002d-1"></a> <p>This expression causes the variable <var>x</var> to be decremented. The value of the expression is the <em>old</em> value of <var>x</var>. </p></dd> </dl> <hr> <div class="header"> <p> Next: <a href="Operator-Precedence.html#Operator-Precedence" accesskey="n" rel="next">Operator Precedence</a>, Previous: <a href="Assignment-Ops.html#Assignment-Ops" accesskey="p" rel="prev">Assignment Ops</a>, Up: <a href="Expressions.html#Expressions" accesskey="u" rel="up">Expressions</a> [<a href="index.html#SEC_Contents" title="Table of contents" rel="contents">Contents</a>][<a href="Concept-Index.html#Concept-Index" title="Index" rel="index">Index</a>]</p> </div> </body> </html>