OperatorMeaning
    ++varvar = var + 1 (expression value is var + 1)
    var++var = var + 1 (expression value is )
    —varvar = var – 1 (expression value is var – 1)
    var—var = var – 1 (expression value is var)
    1. var a, b;
    3. a = 0;
    4. b = ++a; // Increment a before b gets its value.
    5. assert(a == b); // 1 == 1
    6. a = 0;
    7. b = a++; // Increment a AFTER b gets its value.
    8. assert(a != b); // 1 != 0
    10. a = 0;
    11. assert(a == b); // -1 == -1
    13. a = 0;
    14. b = a--; // Decrement a AFTER b gets its value.
    15. assert(a != b); // -1 != 0