CODEWITHSUNDEEP
c++
user16872085
user16872085

Reputation:

Program crash in wstringstream

My program is crashing in the wstringstream line, I think it's because sometimes it searches for a msg that doesn't exist inside of wmTranslation, how I could 'fix' this?

const char* TranslateMessage(int Msg) {
    static std::map<int, const char*> wmTranslation = {
        {0, "WM_NULL" },
        {1, "WM_CREATE" },
        {2, "WM_DESTROY" },
        //...
    };

    const char* translatedMessage = "Unknown message";

    translatedMessage = wmTranslation[Msg];

    return translatedMessage;
}

    const char* translatedMessage = TranslateMessage(Msg);

    std::wstringstream text;
    text << L"Msg: " << Msg << L" - " << translatedMessage;
    OutputDebugString(text.str().c_str());

Upvotes: 1

Views: 69

Answers (1)

molbdnilo
molbdnilo

Reputation: 66371

Looking up a key that doesn't exist adds an entry for the key, with a default value (the null pointer in your case).

Check if the key exists first, then return the relevant value.

const char* TranslateMessage(int Msg) {
    static std::map<int, const char*> wmTranslation = {
        {0, "WM_NULL" },
        {1, "WM_CREATE" },
        {2, "WM_DESTROY" },
        //...
    };
    auto it = wmTranslation.find(Msg);
    return it != wmTranslation.end() ? it->second : "Unknown message";
}

If all the values are consecutive integers from zero upwards, you might consider using a vector (or an array) rather than a map, and index with Msg.

Upvotes: 3

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