Small program to change the screen resolution from the windows command line

setres.cpp

// setres.cpp
// Aswin van Woudenberg

#include <iostream>
#include <windows.h>

using namespace std;

int main(int argc, char *argv[])
{
    int w;
    int h;
    int d;

    DEVMODE sDevMode;
    LONG rVal;

    if (argc!=4) {
        cout << "Usage: setres <width> <height> <depth>" << endl;
        return 1;
    }
    w = atoi(argv[1]);
    h = atoi(argv[2]);
    d = atoi(argv[3]);
    if (!w || !h || !d) {
        cout << "Invalid argument" << endl;
        return 1;
    }

    ZeroMemory(&sDevMode, sizeof(DEVMODE));
    sDevMode.dmSize = sizeof(DEVMODE);
    sDevMode.dmPelsWidth = w;
    sDevMode.dmFields |= DM_PELSWIDTH;
    sDevMode.dmPelsHeight = h;
    sDevMode.dmFields |= DM_PELSHEIGHT;
    sDevMode.dmBitsPerPel = d;
    sDevMode.dmFields |= DM_BITSPERPEL;

    rVal = ChangeDisplaySettings(&sDevMode, CDS_UPDATEREGISTRY);
    switch (rVal)
    {
        case DISP_CHANGE_SUCCESSFUL:
            rVal = SendMessage(HWND_BROADCAST, WM_DISPLAYCHANGE, SPI_SETNONCLIENTMETRICS, NULL);
            return 0;
        case DISP_CHANGE_RESTART:
            cout << "The computer must be restarted in order for the graphics mode to work." << endl;
            return 0;
        case DISP_CHANGE_BADFLAGS:
            cout << "An invalid set of flags was passed in." << endl;
            return 1;
        case DISP_CHANGE_FAILED:
            cout << "The display driver failed the specified graphics mode." << endl;
            return 1;
        case DISP_CHANGE_BADMODE:
            cout << "The graphics mode is not supported." << endl;
            return 1;
        case DISP_CHANGE_NOTUPDATED:
            cout << "Unable to write settings to the registry." << endl;
            return 0;
    }
    return 0;
}