Ammunition is generally described by bullet diameter, case length, and the country that used or introduced it. So, measure the bullet diameter (if the bullets are still in the cases), and the case length and diameter at the base.
Just guessing without photos, but:
* 7.9 TC 1945 is most likely 7.92X57mm, AKA 8mm Mauser. It was used by Germany, Czechoslovakia, Serbia and later Yugoslavia, Persia later Iran, Egypt, Turkey, you name it.
* T 9 A 78 is likely 7.62X39mm ammunition.
* EW 42 could be 303 British