Customizing Error Messages in Custom Exception Types

To provide custom error messages when throwing your own exception types, you can follow these steps:

Step 1: Add a constructor to your exception class that accepts a string parameter representing the error message:

1#include <exception>
2#include <string>
3
4class CustomException : public std::exception {
5 public:
6  explicit CustomException(
7    const std::string& message)
8      : m_errorMessage(message) {}
9
10  // ...
11};

Step 2: Store the error message in a member variable of your exception class:

1class CustomException : public std::exception {
2// ...
3 private:
4  std::string m_errorMessage;
5};

Step 3: Override the what() function to return the custom error message:

1class CustomException : public std::exception {
2 public:
3  // ...
4  const char* what() const noexcept override {
5    return m_errorMessage.c_str();  
6  }
7  // ...
8};

Step 4: When throwing the exception, provide the custom error message as an argument:

1throw CustomException("Something went wrong!");

Now, when you catch the exception, you can access the custom error message using the what() function:

1try {
2  // ...
3} catch (const CustomException& e) {
4  std::cout << "Error: " << e.what();
5}

This way, you can provide informative and specific error messages when throwing your custom exception types.