c language getche question

#include <stdio.h>  

void main()
{

    char ch;

    ch = getche();

    ch = getche();

    ch = getche();


}

It's an example from a book, and if it comes out like this, it has to end with ABC, but I don't know why because it ends with ABI wondered if the laptop was the problem, so I tried it on the school computer, but it ended when I typed AB, so I don't know whyㅜ<

I tried debugging it, but I think there was a text message in the middle, so how can I fix it...