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 certain amount of memory no matter its value? For example, if I created the following integer with the value of 255

int myInt = 255; 

Then myInt would occupy 4 bytes with my compiler. However, the actual value, 255 can be represented with only 1 byte, so why would myInt not just occupy 1 byte of memory? Or the more generalized way of asking: Why does a type have only one size associated with it when the space required to represent the value might be smaller than that size?

Answer 1

Because types fundamentally represent storage, and they are defined in terms of maximum value they can hold, not the current value.

The very simple analogy would be a house - a house has a fixed size, regardless of how many people live in it, and there is also a building code which stipulates the maximum number of people who can live in a house of a certain size.

However, even if a single person is living in a house which can accommodate 10, the size of the house is not going to be affected by the current number of occupants.