How would you use a variable in place of volume in mciSendString? C++

Question

So I am making a basic 2D fighting game using C++. And for sound/audio effects I am using mciSendString()

            mciSendString(TEXT("setaudio sounds\\character_select.mp3 volume to 500"), NULL, 0, NULL);

This above code works fine. It sets the volume of the sound to 500; however, I do not want to hard-code the volume value. I want it to progressively get smaller without having to copy and paste the same line over and over with just a smaller integer value for volume.

            mciSendString(TEXT("setaudio sounds\\character_select.mp3 volume to " + volume ), NULL, 0, NULL);

I want to do something like this. Where instead of having a hard-coded 500 I could have a variable with any integer value in it. However when I run it I get no errors and the audio continues playing like it normally would at 1000 instead of 500.

What would I do to fix this?

Answer 1

Firstly you cannot use the TEXT() macro with variables. It's only meant to be used with character array literals like "Hello" and places an L before the literal, depending on which option (multibyte wide strings or UTF8) is used to compile the code.

For the latter option you can use a std::string variable to compose your command:

std::ostringstream oss;
int volume = 300;
oss << "setaudio sounds\\character_select.mp3 volume to " << volume;
std::string cmd = oss.str();

mciSendString(cmd.c_str(), NULL, 0, NULL);

For the other option, you need to use std::wstring , std::wostringstream accordingly.

Answer 2

I had the same issue with mcisendstring since you are using c++ I recommend you do as I did previously to work this issue out

make a function called mcicommand as follow:

    #include <string>
    string mcicommand(string volume){
    
        string command = "setaudio song volume to ";
        
        int found = command.find_last_of(" ");
        command = command.substr(0, found) + " " + volume;
        
        return command;
}

now whenever you want to call upon this function with mcisendstring do this

string volume;
cin >> volume;
vol_command = mcicommand(volume)
mcisendstring(vol_command.c_str , NULL, 0, NULL);