Exceptions and pre-conditions: Difference between revisions
Mr. MacKenty (talk | contribs) No edit summary |
Mr. MacKenty (talk | contribs) |
||
| Line 14: | Line 14: | ||
<syntaxhighlight lang="python"> | <syntaxhighlight lang="python"> | ||
# here is some Python code with a deliberate error. There should be two apostrophe's for the end argument. | # here is some Python code with a deliberate error. There should be two apostrophe's for the end argument. | ||
print("hello world", end=') | print("hello world", end='') | ||
print("from Warsaw") | print("from Warsaw") | ||
print("=" * 25) | print("=" * 25) | ||
| Line 33: | Line 33: | ||
If you google the exception (line 4) you can often find helpful information about the exception. | If you google the exception (line 4) you can often find helpful information about the exception. | ||
For a list of common exceptions, please [https://www.tutorialspoint.com/python/standard_exceptions.htm click here] | For a list of common exceptions, please [https://www.tutorialspoint.com/python/standard_exceptions.htm click here] | ||
== Standards == | == Standards == | ||
Revision as of 08:08, 27 September 2021
An exception is an anomalous or exceptional condition requiring special processing – often changing the normal flow of program execution[2].
Be careful not to confuse an exception with an error.
An error "indicates serious problems that a reasonable application should not try to catch." An exception "indicates conditions that a reasonable application might want to catch."[3].
We use the term "catch an exception" to catch exceptions and plan how the program should respond.
Example[edit]
# here is some Python code with a deliberate error. There should be two apostrophe's for the end argument.
print("hello world", end='')
print("from Warsaw")
print("=" * 25)
When we execute this code we see the following exception:
You can see there are four lines here:
- on the first line we see the name of the file being executed and the line number where the exception was thrown.
- on the second line we see the line of code where the exception was thrown
- on the third line we see a carat (^) pointing the place where the exception was thrown
- on the fourth line we see the description of the exception
If you google the exception (line 4) you can often find helpful information about the exception. For a list of common exceptions, please click here
Standards[edit]
These standards are used from the IB Computer Science Subject Guide[4]
- Identify exceptions that need to be considered in a specified problem solution.
References[edit]
- ↑ http://www.flaticon.com/
- ↑ https://en.wikipedia.org/wiki/Exception_handling
- ↑ https://stackoverflow.com/questions/5813614/what-is-difference-between-errors-and-exceptions
- ↑ IB Diploma Programme Computer science guide (first examinations 2014). Cardiff, Wales, United Kingdom: International Baccalaureate Organization. January 2012.