Troubleshooting C++ function exceptions: Understand the essence of error handling

Exception handling manages errors in functions through throw and catch statements. The throw statement triggers an exception, and the catch statement catches exceptions based on the exception type. It's crucial to catch exceptions early in your function and provide clear error messages. Choose the right exception type, use generic catch blocks with caution, and handle unknown exceptions appropriately in generic catch blocks.

C Function Exception Troubleshooting: Understanding the Essence of Error Handling

Exception handling is crucial for handling errors and exceptions in functions . Exceptions in C are implemented through throw and catch statements.

throw Statement

throw statement is used to trigger an exception. It receives a throwable object as a parameter, which can be a standard exception type (such as std::runtime_error) or a custom exception type.

catch Statement

catch statement is used to catch exceptions. It accepts an exception type or a generic exception type (std::exception) as a parameter. If the thrown exception type matches the catch block's argument type, the catch block is executed.

Practical Case

Consider a function that calculates the division of two numbers:

double divide(double num1, double num2) {
  if (num2 == 0) {
    throw std::runtime_error("除数不能为 0");
  }
  return num1 / num2;
}

Now consider a function that calls the function and handles the exception Main function:

int main() {
  try {
    double result = divide(10, 2);
    std::cout << "结果：" << result << std::endl;
  }
  catch (std::runtime_error& e) {
    std::cout << "错误：" << e.what() << std::endl;
  }
  catch (...) {
    std::cout << "未知错误" << std::endl;
  }
  return 0;
}

If num2 is 0, the divide function will throw a std::runtime_error exception. The first catch block in the main function will catch the exception and print the error message. If another type of exception is thrown, the second catch block will be executed and "Unknown Error" will be printed.

Understand the essence of error handling

1. Catch exceptions early and handle them properly: Catch exceptions as early as possible in functions and provide meaningful error message.
2. Keep the exception type accurate: The exception type used should accurately describe the exception.
3. Use generic catch blocks with caution: Use generic catch blocks (catch (...)) only when the exception type cannot be predicted.
4. Handle unknown exceptions properly: In a generic catch block, ensure that unknown exceptions are handled appropriately, such as logging or terminating the process.

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