What are the rules for ++ and — operators?

Rules for ++ and – operators: 

Following are the rules for the increment (++) and decrement (–) operators.

1. Increment (++) and decrement (–) operators are unary operators and they require variable as their operands.
2. When postfix ++ (or –) is used with a variable in an expression, the expression is evaluated first using the original value of the variable and then the variable is incremented (or decremented) by one.
3. When prefix ++ (or –) is used in an expression, the variable is incremented (or decremented) first and then the expression is evaluated using the new value of the variable.

The precedence and associatively of ++ and –operators are the same as those of unary + and unary -.