SendInput WinAPI C

#define _WIN32_WINNT 0x0501
#include <windows.h>

int main(void) {

    const UINT fooKey = 65; // ascii value for 'a', ?case ignored?
    const UINT keySize = 2;
    INPUT keyIn[keySize];
    memset(keyIn, 0, sizeof(keyIn));

    keyIn[0].type = INPUT_KEYBOARD;

    // Key pressed down
    keyIn[0].ki.wScan = MapVirtualKey(fooKey, 0); //key we're going to "press"
    keyIn[0].ki.dwFlags = KEYEVENTF_SCANCODE; // wVk is ignored
    keyIn[0].ki.time = 0; // OS can provide timestamp, we don't care
    keyIn[0].ki.dwExtraInfo = 0;

    // Key released/up state
    keyIn[1].ki.wScan = MapVirtualKey(fooKey, 0);
    keyIn[1].ki.dwFlags = KEYEVENTF_SCANCODE | KEYEVENTF_KEYUP; // change state to up
    keyIn[1].ki.time = 0;
    keyIn[1].ki.dwExtraInfo = 0;

    while(1){  // ^C to escape
        // second arg should be array of INPUT objects, but bear with me...
        SendInput(1, keyIn[0], sizeof(INPUT) ); // send down only message
        Sleep(3000); // in ms
        SendInput(1, keyIn[1], sizeof(INPUT) ); // send up message, change state
    }

    return 0;

} // Main