It's not that difficult on its own, but it's complicated when it comes in bundles, so it's a summary.
--Increment "++" ・ ・ ・ Add 1 to the value of the variable --Decrement "-" ・ ・ ・ Subtract 1 to the value of the variable
int a = 5
int b = ++a
↑ Add 1 to a and then substitute for b (b = 6, a = 6)
int a = 5
int b = a++
↑ Substitute in b and then add 1 to a (b = 5, a = 6)
int a=5 int b = a++ + ++a + --a - a-- -a
Or something b = 5 + 7 + 6 - 6 - 5
And the answer is 7