📄 except.htm
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<title> The exception Class</title>
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<font size=5 color=green>Class Name</font> exception
Classification Error Handling
Header File <exception>
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<a href="except.htm#diagram">Class Relationship Diagram</a><br>
<br>
<a href="except.htm#desc">Class Description</a><br>
<h2>Member Classes</h2>
<i>None</i>
<h1>Methods</h1>
<a href="except.htm#exception1">exception() throw();</a><br>
<a href="except.htm#exception2">exception(const exception&) throw();</a><br>
<a href="except.htm#exception3">virtual ~exception() throw();</a><br>
<a href="except.htm#what">virtual const char* what() const throw();</a><br>
<h2>Operators</h2>
<a href="except.htm#operator=">exception& operator=(const exception&) throw();</a><br>
<a href="except.htm#example"><h2>Example</h2></a>
<a name="desc"><h3>Description</h3></a>
<p>
The exception class is the base class for the logic_error and runtime_error
family of classes. It is also the base class for <i>bad_alloc</i>, <i>bad_case,</i> <i>bad_exception,</i>
<i>bad_typeid,</i> and <i>ios_base::failure.</i> The standard C++ library uses the exception family
of classes to report errors that occur in the execution of some of the methods within
the class library. Exception objects are not thrown by all methods in the standard
class library. Furthermore Exception class objects are not used at all to report
errors in the standard library functions that come from the C standard library.
</p>
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<pre>
<a name="exception1">Method exception()</a>
Access Public
Classification Constructor
Syntax exception throw();
Parameters None
Return None
</pre>
<h3>Description</h3>
<p>
This exception() method constructs an object of type exception.
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<a name="exception2">Method exception()</a>
Access Public
Classification Constructor
Syntax exception(const exception &X) throw();
Parameters X is an exception class that will be used in a copy operation.
Return None
</pre>
<h3>Description</h3>
<p>
This exception() method is used whenever copies or temporary copies of objects of this
type are needed. This method is called whenever an object of this type is:
<pre>
passed by value
used as a return type by value
used to initialize another object of this type
</pre>
</p>
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<pre>
<a name="exception3">Method exception()</a>
Access Public
Classification Destructor
Syntax virtual ~exception() throw();
Parameters None
Return None
</pre>
<h3>Description</h3>
<p>
This method destroys an object of this type. Since this method is virtual it may be overridden
in a derived class.
</p>
<hr>
<pre>
<a name="what">Method what()</a>
Access Public
Classification Destructor
Syntax virtual const char* what() const throw()
Parameters None
Return The what() method returns a description or explanation for the exception
that was thrown.
</pre>
<h3>Description</h3>
<p>
This method returns a description of the error that objects of this class report.
This method can also be used to return explanations as well as possible corrective
steps.
</p>
<hr>
<pre>
<a name="operator=">Method operator=()</a>
Access Public
Classification Operator
Syntax exception& operator=(const exception &X) throw();
Parameters X is an exception object that will be copied into the
current exception object.
Return The assignment operator returns a reference to the current
object.
</pre>
<h3>Description</h3>
<p>
This definition of the assignment operator assigns X to the current exception object.
</p>
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<a name="diagram"><img src="except.gif"></a>
<a name="example"></a>
<img src="lego.gif">
<pre>
1
2 #include <exception>
3
4
5 void main(void)
6 {
7
8
9 try{
10
11 exception X;
12 throw(X);
13 }
14 catch(const exception &X)
15 {
16 cout << X.what() << endl;
17
18 }
19
20 try
21 {
22 logic_error Logic("Logic Mistake");
23 throw(Logic);
24 }
25 catch(const exception &X)
26 {
27 cout << X.what() << endl;
28 }
29
30
31
32 }
33
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