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<!-- %MENU% Utilities for copying and comparing strings and arrays -->
<h2 class="chapter">5 String and Array Utilities</h2>

<p>Operations on strings (or arrays of characters) are an important part of
many programs.  The GNU C library provides an extensive set of string
utility functions, including functions for copying, concatenating,
comparing, and searching strings.  Many of these functions can also
operate on arbitrary regions of storage; for example, the <code>memcpy</code>
function can be used to copy the contents of any kind of array.

   <p>It's fairly common for beginning C programmers to &ldquo;reinvent the wheel&rdquo;
by duplicating this functionality in their own code, but it pays to
become familiar with the library functions and to make use of them,
since this offers benefits in maintenance, efficiency, and portability.

   <p>For instance, you could easily compare one string to another in two
lines of C code, but if you use the built-in <code>strcmp</code> function,
you're less likely to make a mistake.  And, since these library
functions are typically highly optimized, your program may run faster
too.

<ul class="menu">
<li><a accesskey="1" href="Representation-of-Strings.html#Representation-of-Strings">Representation of Strings</a>:    Introduction to basic concepts. 
<li><a accesskey="2" href="String_002fArray-Conventions.html#String_002fArray-Conventions">String/Array Conventions</a>:     Whether to use a string function or an
				 arbitrary array function. 
<li><a accesskey="3" href="String-Length.html#String-Length">String Length</a>:                Determining the length of a string. 
<li><a accesskey="4" href="Copying-and-Concatenation.html#Copying-and-Concatenation">Copying and Concatenation</a>:    Functions to copy the contents of strings
				 and arrays. 
<li><a accesskey="5" href="String_002fArray-Comparison.html#String_002fArray-Comparison">String/Array Comparison</a>:      Functions for byte-wise and character-wise
				 comparison. 
<li><a accesskey="6" href="Collation-Functions.html#Collation-Functions">Collation Functions</a>:          Functions for collating strings. 
<li><a accesskey="7" href="Search-Functions.html#Search-Functions">Search Functions</a>:             Searching for a specific element or substring. 
<li><a accesskey="8" href="Finding-Tokens-in-a-String.html#Finding-Tokens-in-a-String">Finding Tokens in a String</a>:   Splitting a string into tokens by looking
				 for delimiters. 
<li><a accesskey="9" href="strfry.html#strfry">strfry</a>:                       Function for flash-cooking a string. 
<li><a href="Trivial-Encryption.html#Trivial-Encryption">Trivial Encryption</a>:           Obscuring data. 
<li><a href="Encode-Binary-Data.html#Encode-Binary-Data">Encode Binary Data</a>:           Encoding and Decoding of Binary Data. 
<li><a href="Argz-and-Envz-Vectors.html#Argz-and-Envz-Vectors">Argz and Envz Vectors</a>:        Null-separated string vectors. 
</ul>

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