Increment and Decrement Operators
Adding or subtracting 1 from a variable is a very common
programming practice. Adding 1 to a variable is called incrementing
and subtracting 1 from a variable is called decrementing.
increment and decrement operators work only with integer
variables -- not on floating point variables or literals.
the C++ compiler is controlling the execution of the prefix and postfix
operators. You cannot change this order of execution. For
parentheses below will not force an early execution:
value = (((x--)))* num; //still
decrements x last.
one disadvantage of using the increment/decrement
operators is that the variable can only be incremented or
decremented by the value ONE. If you need to increment (or
decrement) by a larger (or smaller) value, you
must use statements like
m += 2; or
amount -= 5;
be careful when combining increment and
decrement operators inside expressions with logical operators. If in
doubt, don't use them together. For example, do NOT use:
if (( num1 = = 4 ) || ( num2 != ++j))
(j may not be incremented when (num1 = =
4) is TRUE.)
Instead, separate the code to avoid this problem:
if (( num1 = = 4) || (num2 != j))
All are the same:
i = i + 1;
i += 1;
increment or decrement occurs before
the variable's value is used in the
remainder of the expression.
increment or decrement occurs after
the variable's value is used in the remainder of the expression.