这个警告在 C++ 中对于异常处理意味着什么？

Question

我写了除法运算异常处理的代码：
我包括了 Zero division error、Negative value error（不是例外，但我包括了它！）和 Indeterminate form error（我也包括了它）。

然后在编译后它显示了一些警告，但是 .exe 文件是运行正如预期的那样。
这是我编译后收到的代码和输出。

代码

#include <iostream>
#include <stdexcept>

using namespace std;

int main(void)
{
    int numerator, denominator, quotient, remainder;
    cout << "Enter the value of numerator and denominator: ";
    cin >> numerator >> denominator;
    try
    {
        if (!numerator && !denominator)
        {
            throw logic_error("Logical Error: Indeterminate Form!\n");
        }
        else if (!denominator)
        {
            throw runtime_error("Math Error: Attemp to divide by zero!\n");
        }

        else if (numerator < 0 || denominator < 0)
        {
            throw invalid_argument("Invalid Arguments: Negative numbers not allowed!\n");
        }
        else
        {
            quotient = numerator / denominator;
            remainder = numerator % denominator;
            cout << "The result after division is:\n"
                 << "Quotient: " << quotient << "\nRemainder: " << remainder << '\n';
        }
    }
    catch (logic_error &exc)
    {
        cout << exc.what();
    }
    catch (runtime_error &exc)
    {
        cout << exc.what();
    }
    catch (invalid_argument &exc)
    {
        cout << exc.what();
    }
    catch (...)
    {
        cout << "Some Exception Occured!\n";
    }

    cout << "\nProgram Finished...\n";
    return 0;
}

输出

Exceptional_Handling_05.cpp: In function 'int main()':
Exceptional_Handling_05.cpp:42:5: warning: exception of type 'std::invalid_argument' will be caught
   42 |     catch (invalid_argument &exc)
      |     ^~~~~
Exceptional_Handling_05.cpp:34:5: warning:    by earlier handler for 'std::logic_error'
   34 |     catch (logic_error &exc)
      |     ^~~~~
Enter the value of numerator and denominator: 52 0
Math Error: Attemp to divide by zero!

Program Finished...

这里的警告是什么意思？
尽管对于每个角落和异常情况，程序的输出都符合预期。

Answer 1

触发相同警告的精简代码版本是：

#include <iostream>
#include <stdexcept>

int main()
{
    int numerator = -1, denominator = -1;
    try
    {        
        if (numerator < 0 || denominator < 0)
        {
            throw std::invalid_argument("Invalid Arguments: Negative numbers not allowed!\n");
        }
    }
    catch (std::logic_error &exc)
    {
        std::cout << exc.what();
    }
    catch (std::invalid_argument &exc)
    {
        std::cout << " THIS IS NEVER REACHED !!";
        std::cout << exc.what();
    }
}

输出是

Invalid Arguments: Negative numbers not allowed!

因为 std::invalid_argument 继承自 std::logic_error 并且第一个 catch 已经处理了异常。如果你想分别捕获一般的 logic_error 和更专业的 invalid_argument，你需要以相反的顺序进行：

catch (std::invalid_argument &exc)
{
    std::cout << exc.what();
}
catch (std::logic_error &exc)
{
    std::cout << exc.what();
}

Answer 2

invalid_argument 源自logic_error，代码从上到下执行。这意味着异常将首先被 logic_error 捕获。 invalid_argument 是多余的，可以删除

这个警告在 C++ 中对于异常处理意味着什么？

What does this warning mean in C++ for exception handling?

c++

exception

try-catch