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Topics

C++ Basics

Introduction to C++C++ History and EvolutionC++ Environment SetupC++ First ProgramC++ SyntaxC++ CommentsC++ Data TypesC++ VariablesC++ ConstantsC++ KeywordsC++ OperatorsC++ Input/Output

C++ Control Structures

C++ If-Else StatementsC++ Switch StatementsC++ For LoopsC++ While LoopsC++ Do-While LoopsC++ Break and ContinueC++ Goto Statement

C++ Functions

C++ Function BasicsC++ Function ParametersC++ Function OverloadingC++ Inline FunctionsC++ RecursionC++ Default ArgumentsC++ Lambda Expressions

C++ Arrays and Strings

C++ ArraysC++ Multidimensional ArraysC++ C-style StringsC++ String ClassC++ String FunctionsC++ String Streams

C++ Pointers and References

C++ Pointers BasicsC++ Pointer ArithmeticC++ ReferencesC++ Pointers vs ReferencesC++ Dynamic Memory AllocationC++ Smart Pointers

C++ Object-Oriented Programming

C++ Classes and ObjectsC++ Constructors and DestructorsC++ Access SpecifiersC++ EncapsulationC++ InheritanceC++ PolymorphismC++ Virtual FunctionsC++ Abstract ClassesC++ Interfaces (Pure Virtual)C++ Friend Functions and Classes

C++ Templates

C++ Function TemplatesC++ Class TemplatesC++ Template SpecializationC++ Variadic Templates

C++ Exception Handling

C++ Try-Catch BlocksC++ Throwing ExceptionsC++ Custom ExceptionsC++ Exception Specifications

C++ File Handling

C++ File I/O StreamsC++ Reading from FilesC++ Writing to FilesC++ Binary File Operations

C++ Standard Template Library

C++ STL ContainersC++ STL AlgorithmsC++ STL IteratorsC++ STL Function Objects

C++ Advanced Topics

C++ NamespacesC++ Preprocessor DirectivesC++ Type CastingC++ MultithreadingC++ Regular ExpressionsC++ Move SemanticsC++ Rvalue References

C++ Memory Management

C++ Stack vs HeapC++ Memory LeaksC++ Garbage CollectionC++ Custom Allocators

C++ Best Practices

C++ Coding StandardsC++ Performance OptimizationC++ Debugging TechniquesC++ Unit Testing

C++ Custom Exceptions

Custom exceptions in C++ allow developers to create specialized error-handling mechanisms tailored to their specific application needs. By extending the standard exception classes, you can provide more detailed and context-specific error information.

Creating Custom Exception Classes

To create a custom exception in C++, you typically derive a new class from the standard std::exception class or one of its derived classes. This approach ensures compatibility with existing exception-handling mechanisms.


#include <exception>
#include <string>

class CustomException : public std::exception {
private:
    std::string message;

public:
    explicit CustomException(const std::string& msg) : message(msg) {}

    const char* what() const noexcept override {
        return message.c_str();
    }
};

In this example, we've created a CustomException class that stores a custom error message and overrides the what() function to return this message.

Using Custom Exceptions

Once you've defined your custom exception class, you can throw and catch it just like any other exception in C++. Here's an example of how to use the CustomException we created:


#include <iostream>

void riskyFunction(int value) {
    if (value < 0) {
        throw CustomException("Negative value not allowed");
    }
    // Process the value...
}

int main() {
    try {
        riskyFunction(-5);
    } catch (const CustomException& e) {
        std::cout << "Caught custom exception: " << e.what() << std::endl;
    }
    return 0;
}

This code demonstrates how to throw the custom exception and catch it in a try-catch block.

Best Practices for Custom Exceptions

  • Derive from std::exception or its subclasses for consistency.
  • Provide meaningful error messages that help diagnose the problem.
  • Use custom exceptions to represent specific error conditions in your application domain.
  • Keep exception classes small and focused on error reporting.
  • Consider creating a hierarchy of custom exceptions for complex applications.

Exception Hierarchies

For larger projects, you might want to create a hierarchy of custom exceptions. This approach allows for more granular error handling and can make your code more maintainable.


class DatabaseException : public std::exception {
    // ... implementation ...
};

class ConnectionException : public DatabaseException {
    // ... implementation ...
};

class QueryException : public DatabaseException {
    // ... implementation ...
};

With this hierarchy, you can catch specific types of database-related exceptions or handle them more generally.

Performance Considerations

While custom exceptions provide great flexibility in error handling, it's important to use them judiciously. Throwing and catching exceptions can have performance implications, especially in performance-critical code paths.

Remember: Exceptions should be used for exceptional circumstances, not for regular control flow.

For more information on exception handling in C++, you might want to explore throwing exceptions and exception specifications.

Conclusion

Custom exceptions in C++ provide a powerful mechanism for handling application-specific errors. By creating your own exception classes, you can enhance the error-handling capabilities of your C++ programs, making them more robust and easier to debug.