Why the size of a structure is bigger than it should be?

Question

https://code.sololearn.com/cc4Hoh73DPz2/?ref=app

Why size of a structure test is 16, not 12 as it should be? It seems like compilator is filling space to an iteration of 8, but why? It is not doing that for a class/structure with a single element.

Answer 1

To solve this, just add the following line :
#pragma pack(1)

This will force the compiler to use a byte padding of one, which will ensure that extra memory is not used.

By default, in memory, some blocks of a fixed number of size are used to store data. The size of these blocks is determined usually by the last member or the largest sized member of the class. As a result, the blocks were 8 bytes each and 4 bytes were wasted. So if you force a block size of one, the problem of extra bytes no longer occurs.