For 2021 - online Python 3 training - see ((here)).
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Throwing your own exception in C++, and catching it
In C++ you can throw anything - it doesn't have to be something "throw-able" as in Java.
1. Create a class of objects that you want to throw in exceptional circumstances
2. When you want to throw an exception, use the throw keyword and pass in the object
3. Call the code that you want to catch the exception in a try block and
4. Add catch blocks after the try block to handle the exceptions.
Full example, with comments, [here].
There's a program using string objects - here - that shows how some of the C++ system classes throw exceptions ...
92:antrim graham$ ./prob
Please enter your details I am Graham Ellis and I am in Belfast at present
terminate called after throwing an instance of 'std::out_of_range'
  what(): basic_string::erase
Abort trap
92:antrim graham$
And here is a similar program but with an added exception handler:
92:antrim graham$ ./except
Please enter your details This is a further demonstration for you
Caught exception basic_string::erase
We could go on if we wanted
Although in this demo we'll exit nice
92:antrim graham$
See [here] for the failing code and [here] for the fixed code. (written 2010-11-24, updated 2010-12-04)
Associated topics are indexed as below, or enter http://melksh.am/nnnn for individual articles C236 - C and C based languages - Exceptions [799] The case for exceptions - (2006-07-11) [1875] What are exceptions - Python based answer - (2008-11-08) [2622] Handling unusual and error conditions - exceptions - (2010-02-03) [3509] Operator Overloading, Exceptions, Pointers, References and Templates in C++ - new examples from our courses - (2011-11-06)
Some other Articles
Finding elements common to many lists / arraysWell House Price list, January to March 2011Belfast, on a cold November eveningStrings, Garbage Collection and Variable Scope in C++Throwing your own exception in C++, and catching itUsing C and C++ functions in the same program - how to do itSeparating groups of variables into namespacesPictures from the Birkenhead to Belfast crossingOn the way to the course this weekComments in and on Perl - a case for extreme OO programming
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This is a page archived from The Horse's Mouth at
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