Well you've got num, right? That's your array. num[0] is the first number, num[1] is the second number, etc.
The only difficulty is that four bytes may or may not even get you one number, depending on your system. You should make your buffer as big as you need it.
There's also no good reason for you to make your buffer of type char.
Code:int big_pile_of_numbers[1000]; file.read(reinterpret_cast<char*>big_pile_of_numbers, sizeof(big_pile_of_numbers));