How to handle exception handling in C++ class design?

In C++ class design, exception handling is used to handle runtime errors and exceptions. Declaring and throwing exceptions through the throw keyword, and catching exceptions through the try-catch statement. The C++ standard library provides many built-in exception classes, such as std::runtime_error and std::invalid_argument. Practical case of exception handling: Define a custom exception class FileReadError to handle file reading errors, and use try-catch statements to capture exceptions and provide friendly error messages.

Exception handling in C++ class design

In C++ class design, exception handling is a crucial mechanism , used to deal with runtime errors and other abnormal situations. This article will guide you on how to handle exceptions and provide a practical example.

Declaration and throwing of exceptions

Exceptions are declared and thrown through the throw keyword. For example:

class MyException : public std::exception {
public:
    const char* what() const noexcept override {
        return "This is an example of a custom exception.";
    }
};

void foo() {
    // 抛出自定义异常。
    throw MyException();
}

Exception capture

Exceptions can be captured through the try-catch statement. try blocks contain code that may throw exceptions, while catch blocks catch specific types of exceptions. For example:

void bar() {
    try {
        foo();  // 可能抛出 MyException。
    } catch (const MyException& e) {
        std::cerr << e.what() << std::endl;  // 输出异常信息。
    }
}

Standard Library Exceptions

The C++ standard library provides many built-in exception classes, such as std::runtime_error and std ::invalid_argument. These exceptions are used to handle common errors such as memory allocation failures and invalid parameters.

Practical Case

The following is a practical case that demonstrates how to use exception handling to handle file read errors:

#include <fstream>
#include <iostream>

class FileReadError : public std::runtime_error {
public:
    using std::runtime_error::runtime_error;
};

void read_file(const std::string& filename) {
    std::ifstream file(filename);
    if (!file.is_open()) {
        throw FileReadError("Could not open file.");
    }
    // 读取文件内容并进行处理...
}

int main() {
    try {
        read_file("my_file.txt");  // 可能抛出 FileReadError。
    } catch (const FileReadError& e) {
        std::cerr << "File read error: " << e.what() << std::endl;
        return 1;  // 非零表示错误。
    }
    return 0;
}

Conclusion

Exception handling is a powerful tool in C++ class design that can help you deal with runtime errors and exceptions. By using try-catch statements and throwing appropriate exceptions, you can create robust and user-friendly code.

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