C++ Primer Plus

Prefixing Versus Postfixing

Clearly, whether you use the prefix or postfix form makes a difference if the value is used for some purpose, such as a function argument or assigning to a variable. But what if the value of an increment or decrement expression isn’t used? For example, are

x++;

and

++x;

different from one another? Or are

for (n = lim; n > 0; --n)    ...;

and

for (n = lim; n > 0; n--)    ...;

different from one another?

Logically, whether the prefix or postfix forms are used makes no difference in these two situations. The values of the expressions aren’t used, so the only effects are the side effects. Here the expressions using the operators are full expressions, so the side effects of incrementing x and decrementing n are guaranteed ...