As you program, you'll often encounter situations in which you need to add or subtract one to or from a number. Quite frequently this occurs within loops, as you'll see in Chapter 6, “Control Structures.” For this reason, C has the increment and decrement operators:
int a = 10; a++; /* 11 */ a++; /* 12 */ a--; /* 11 */
These operators come in both the postfix (shown above) and prefix (below) versions, differing only in precedence (see the next section of the chapter for more):
int a = 10; --a; /* 9 */ ++a; /* 10 */
When assigning the value of an incremented or decremented variables to another variable, which form you use makes all the difference, as the following example will demonstrate.