This first version of Ear Trainer just selects a random interval and a starting note, then plays once the interval and waits. You can try to insert your guess in the entry box and press the [return] key to ask Ear Trainer to check it out. If it's ok, the program will write "Right!" in the status line, else a Wrong!" message will appear.
If you need to re-hear the interval, press the [Replay] button as many times as you want. To skip the current interval press the [Next] button: Ear Trainer will select another random interval and will play it (starting every time from a different note). [?] just prints my name and the program version in the status line and [Exit] closes the Ear Trainer window.
The [Options] button opens the options windows, from where you can modify the way Ear Trainer selects the intervals. Turning on or off some check button you can allow the program to ask you for minor intevals, chromatic intervals, compound and descending intervals. You can also decide whether or not Ear Trainer can repeat an interval. These setting can be saved on disk to be reloaded the next run.
Here you can find gzipped Ear Trainer's source code and binaries.