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<title>PTypes: string: operators</title>
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<p><a href="../index.html"><img src="title-21.png" width="253" height="39" alt="C++ Portable Types Library (PTypes) Version 2.1" border="0"></a>
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<p class="hpath"><a href="index.html">Top</a>: <a href="basic.html">Basic types</a>:
<a href="string.html">string</a>: Operators</p>
<blockquote>
<pre class="lang">#include <ptypes.h>
class string {
<span class="comment"> // assignment</span>
string& operator =(const char*);
string& operator =(char);
string& operator =(const string&);
friend void assign(string&, const char* buf, int len);
<span class="comment"> // concatenation</span>
string& operator +=(const char*);
string& operator +=(char);
string& operator +=(const string&);
string operator +(const char*) const;
string operator +(char) const;
string operator +(const string&) const;
friend string operator +(const char*, const string&);
friend string operator +(char c, const string&);
<span class="comment"> // comparison</span>
bool operator ==(const char*) const;
bool operator ==(char) const;
bool operator ==(const string&) const;
bool operator !=(const char*) const;
bool operator !=(char c) const;
bool operator !=(const string&) const;
<span class="comment"> // indexed character access, 0-based</span>
char& string::operator[] (int index);
const char& string::operator[] (int index) const;
}</pre>
</blockquote>
<p>The string class defines the following binary operators: assignment (<span class="lang">=</span>),
concatenation (<span class="lang">+</span>), concatenation with assignment (<span class="lang">+=</span>)
and comparison (<span class="lang">==</span>,<span class="lang"> !=</span>). At
least one of the operands (either left or right) must be of type <span class="lang">string</span>.
Another operand can be one of the following: <span class="lang">char</span>, <span class="lang">char*</span>
or <span class="lang">string</span>.</p>
<p>Indexed access operator allows to store or retrieve a value of an individual
character. The index is 0-based. When compiled with either <span class="lang">DEBUG</span>
or <span class="lang">CHECK_BOUNDS</span> conditional symbol, bounds checking
is performed for the indexed access; if the index is out of bounds (i.e. less
than 0 or equals to or greater than the length of the string), an unrecoverable
error is raised. The non-debugging version of the library never checks for index
overlfows, thus making your program somewhat faster but less safe.</p>
<p><b>Examples</b></p>
<blockquote>
<pre>string s1 = "abc", s2 = 'd', s3;
s3 = s1 + s2;
s2 += "ef";
s3[2] = 'B';
</pre>
</blockquote>
<p class="seealso">See also: <a href="string.constructors.html">Constructors/destructors</a>,
<a href="string.typecasts.html">Typecasts</a>, <a href="string.manipulation.html">Manipulation</a>,
<a href="string.conversion.html">Conversion</a></p>
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