C++/SDL2 Mixer - One ternary works correctly, but a nearly-identical one doesn't?

Question

I'm writing some simple test audio code to make sure SDL_mixer works for my application, but in the code to change the volume when given certain characters from std::cin everything works except for subtracting 10 from the volume. Adding 10 works, subtracting 1 works, but subtracting 10 only subtracts 1 and not 10.

In the code below, the variable sound is a struct containing 2 maps called mus and eff, indexed by strings and containing Mix_Music* and Mix_Chunk variables respectively. "Moon Patrol" is my music audio and "Pew" is my test effect audio. Also, sorry about the big if/else statement, I'm going to be using GLUT keys for input in the actual program.

Relevant Code:

Mix_PlayMusic(sound.mus["Moon Patrol"], -1);
    char i = ' ';

    std::cout << "i / k: volume +/- 1 | u / j: volume +/- 10 | q: quit | v: pew sound" << std::endl;

    while (i != 'q')
    {
        std::cin >> i;
        int cVolume = Mix_VolumeMusic(-1);
        if (i == 'i') Mix_VolumeMusic(cVolume + ((1) ? cVolume < 128 : 0));           // +1  Works
        else if (i == 'k') Mix_VolumeMusic(cVolume - (1 ?  cVolume > 0 : 0));         // -1  Works
        else if (i == 'u') Mix_VolumeMusic(cVolume + (10 ? cVolume + 10 <= 128 : 0)); // +10 Works
        else if (i == 'j') Mix_VolumeMusic(cVolume - (10 ? cVolume > 9 : 0));         // -10 Doesn't Work
        else if (i == 'p') std::cout << cVolume << std::endl;                         // Showing Volume Works
        else if (i == 'v') Mix_PlayChannel(-1, sound.eff["Pew"], 0);                  // Effect Works
    }                                                                                 // Exiting works

Things I've tried that didn't work:

• Replacing cVolume with Mix_VolumeMusic(-1) everywhere
• Putting the 10 in parentheses
• Changing the key from 'j' to 'f'

Things I've tried that worked as written (but not what I want):

• Changing the 10 to a 1 (code subtracted 1 as told)
• Commenting out the ternary, getting else if (i == 'j') Mix_VolumeMusic(cVolume - (10));// ? cVolume > 9 : 0)); (subtracts 10 correctly but doesn't protect from negative values)

This shows that it's something about the ternary, but the code for subtracting 1 and subtracting 10 is essentially identical. Is there something I'm missing?

Answer 1

The ternary operator works like this:

variable = (condition) ? expressionTrue : expressionFalse;