How to handle exceptions efficiently in C++ using STL?

Effective use of STL exception handling: Use try blocks in blocks of code that may throw exceptions. Use a catch block to handle specific exception types, or a catch(...) block to handle all exceptions. Custom exceptions can be derived to provide more specific error information. In practical applications, STL's exception handling can be used to handle situations such as file read errors. Follow best practices, handle exceptions only when necessary, and keep exception handling code simple.

#How to effectively handle exceptions in C++ using STL?

Exception handling is crucial for handling runtime errors and restoring the execution flow. The C++ Standard Library (STL) provides a rich exception handling mechanism to enable developers to handle exceptions effectively.

Basic usage of exceptions

To handle exceptions, you need to perform the following steps:

1. In the code block that may cause an exception, place The code is placed in try blocks.
2. Use catch blocks to handle specific exception types.
3. If the exception type is unknown, you can use the catch(...) block to handle all exceptions.

Example: Divide by zero

try {
  int x = 0;
  int y = 5;
  int result = y / x; // 引发异常
} catch (const std::runtime_error& e) {
  std::cerr << "运行时错误：" << e.what() << "\n";
}

Custom exception

You can use std:: exception class derives custom exceptions.

class MyException : public std::exception {
public:
  explicit MyException(const char* message) : std::exception(message) {}
};

Exception handling practical cases

In the following cases, STL's exception handling is used to handle file read errors:

try {
  std::ifstream file("data.txt");
  if (!file.is_open()) {
    throw std::runtime_error("无法打开文件");
  }
  // ... 其他文件操作 ...
} catch (const std::runtime_error& e) {
  std::cerr << "文件错误：" << e.what() << "\n";
}

Best Practice

• Handle exceptions only when really needed.
• Keep exception handling code simple.
• Use specific exception types instead of generic catch() blocks.
• Don't throw an exception in the destructor.

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