The document discusses exception handling in C++. It explains that exceptions provide a way to transfer control from one part of a program to another in response to problems. The key concepts are try, catch, and throw blocks. Try blocks identify code that can throw exceptions. Catch blocks catch and handle exceptions. Throw blocks cause exceptions to be thrown. The document provides examples of using try, catch, and throw to handle exceptions like division by zero. It also summarizes several standard C++ libraries that provide common functions and templates.

1. UNIT - III
C++ PROGRAMMING ADVANCED
FEATURES

2. EXCEPTION HANDLING
• An exception is a problem that arises during the
execution of a program. A C++ exception is a
response to an exceptional circumstance that arises
while a program is running, such as an attempt to
divide by zero.
• Exceptions provide a way to transfer control from
one part of a program to another.
• C++ exception handling is built upon three
keywords: try, catch and throw.

3. • try: A try block identifies a block of code for which
particular exceptions will be activated. It's followed
by one or more catch blocks.
• catch: A program catches an exception with an
exception handler at the place in a program where
you want to handle the problem. The catch keyword
indicates the catching of an exception.
• throw: A program throws an exception when a
problem shows up. This is done using
a throw keyword.

4. Syntax for try/catch block:
try
{
// protected code
}
catch( ExceptionName e1 )
{
// catch block
}
catch( ExceptionName e2 )
{
// catch block
}
catch( ExceptionName eN )
{
// catch block
}

5. Throwing Exceptions
• Exceptions can be thrown anywhere within a
code block using throw statements.
Syntax:
throw(exception);
throw exception;
throw;

6. Exception handling using try, throw
and catch expression
Try block
Involves a function which
contains an exception
Catch block
Catches and handles the
exception
Throw block
Function that causes
an exceprion

7. Example Program:
int main()
{
int x = -1;
cout << "Before try n";
try {
cout << "Inside try n";
if (x < 0)
{
throw x;
cout << "After throw (Never executed) n";
}
}
catch (int x ) {
cout << "Exception Caught n";
}
cout << "After catch (Will be executed) n";
return 0;
}
Output:
Before try
Inside try
Exception Caught
After catch (Will be executed)

8. Divide by Zero
int main()
{
int dividend, divisor, quotient;
try
{
cout<<“enter the dividend:”;
cin>>dividend;
cout<<“enter the divisor:”;
cin>>divisor;
if(divisor==0)
throws divisor;
quotient=dividend/divisor;
Cout<<“Quotient=“<<quotent;
}
catch(int)
{
cout<<“Division by Zero”;
}
return 0;
}

9. STANDARD LIBRARIES
• Standard function library:
– It consists of general-purpose and stand alone
functions that are not part of any class.
– These functions perform essential services such as
• Input
• Output
• Implementation of other operations
It is inherited from C.

10. • Object oriented class library:
– It consists of a collection of classes and associated
functions.
– It support common activities, including
• I/O
• Strings
• Numeric processing

11. The standard C++ library includes
• The language support library
• The diagnostics library
• The general utility library
• The standard string template
• Localization classes and template
• The standard template library
• The standard numerics library
• The standard I/O library
• C++ header for the standard C library

12. The language support library
• It defines types and functions that will be used
implicitly by c++ programs.
• <new> - low level memory management utilities
• <memory> - higher level memory management
utilities
• <delete> - to deallocate the memory
• <exception> - exception handling utilities
• <typeinfo> - runtime information utilities

13. The diagnostics library
• Used to detect and report error conditions
• <stdexcept> - standard exception objects
• <system_error> - a platform_dependent error
code
• <cerrno> - macro containing the last error
number

14. The general utility library
• Especially by the STL which includes
Containers, Iterators and Algorithms libraries.
• <utility> - including utility components
• <cstdlib> - general purpose utilities:random
numbers, program control, sorting
and searching
• <ctime> - C style time/date utilities

15. The standard string template
• <ctype> - functions to determine the type
contained in C data
• <cstring> - character string handling functions
• <string> - handles string class functionalities

16. Localization classes and template
• Localization library permits a C++ program to
address the cultural differences of its various
users.
• <locale> - Localization utilities
• <clocale> - C Localization utilities
• <codecvt> - unicode convertion facilities

17. The standard template library
• Container
– <vector>
– <list>
– <set>
– <multiset>
– <map>

18. • Iterators :
– <iterator>
Algorithm:
• <algorithm>

19. The standard I/O libraries
• <iostream>
• <fstream>
• <sstream>
• <iomanip>
• <cstdio>