How do you do ``?'' to create space

Hi, i am learning C++ and i understund pretty well how it's working.

asigment, pointers, type and size in bits of different values, loop, mathematic operation, objets...

i can read the code and understund what it mean, what it do in mathematical ways.


what i did't understund, or perharps i just did't read this part is how you create the notion of space, angle, lenght.

easy to say, x=2 is 1 after x=1, but what about he is 1 meter more far in this direction
and those two are 2 vertice who make a edge, and those 3 vertice form 3 edge who form a face. and what look like a face.

near bottom (machine) i undertund, near top i understund, but betwen how you create the spatial mark, i did't find yet.

Units are implicit to the code. You decide on what unit to use and enforce it by convention. The code you write provides the semantics or meaning to the values. Computation in the end doesn't care about units, just that your input and output data is consistent.