Why are types always a certain size no matter its value?

Question

Implementations might differ between the actual sizes of types, but on most, types like unsigned int and float are always 4 bytes. But why does a type always occupy a certai

Answer 1

so why would myInt not just occupy 1 byte of memory?

Because you told it to use that much. When using an unsigned int, some standards dictate that 4 bytes will be used and that the available range for it will be from 0 to 4,294,967,295. If you were to use an unsigned char instead, you would probably only be using the 1 byte that you're looking for, (depending on the standard and C++ normally uses these standards).

If it weren't for these standards you'd have to keep this in mind: how is the compiler or CPU supposed to know to only use 1 byte instead of 4? Later on in your program you might add or multiply that value, which would require more space. Whenever you make a memory allocation, the OS has to find, map, and give you that space, (potentially swapping memory to virtual RAM as well); this can take a long time. If you allocate the memory before hand, you won't have to wait for another allocation to be completed.

As for the reason why we use 8 bits per byte, you can take a look at this: What is the history of why bytes are eight bits?

On a side note, you could allow the integer to overflow; but should you use a signed integer, the C\C++ standards state that integer overflows result in undefined behavior. Integer overflow