"increments" "decrements" after and before

Question

how this really go, I dont understand nothing

Answer 1

preincrement/predecrement (++x) has higher precedence, or priority, than postincrement/postdecrement (x++). So which you use changes when it operates.
Ex: ++x will add/subtraxt 1 to x first and foremost. Then, all other operations around it will use the new value.
x++ will use the old value for x until all other operations are done. Then, 1 is added/subtracted.

Answer 2

thanks