In C++, the compiler relies entirely on the programmer's type annotations.

This basically means that the compiler will just take it as truth and then continue onwards. However if you are trying to cast an int to another type of variable it might result in a undefined behaviour.

Only if you want a bit more in-depth look at the situation:
The compiler uses different types of assembly instructions for the different types. Those are specific for every type. For example, using the same instructions that you use on a float, on an integer variable will probably result in undefined behaviour or other errors like segmentation fault.

There is no additional address or anything, its just the memory needed for the type (e.g., 1 byte for int8_t) which are assigned in the memory.