5.12 Operators for Performing Shortcuts

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C++ not only provides you with a rich set of declarations, but also gives you a large number of special-purpose operators. Frequently a programmer wants to increment (add 1 to) a variable. Using a normal assignment statement, this would look like:

 total_entries = total_entries + 1; 

C++ provides you a shorthand for performing this common task. The ++ operator is used for incrementing:

 ++total_entries; 

A similar operator, -- , can be used for decrementing (subtracting 1 from) a variable.

 --number_left;  // Is the same as number_left = number_left - 1; 

But suppose you want to add 2 instead of 1. Then you can use the following notation:

 total_entries += 2; 

This is equivalent to:

 total_entries = total_entries + 2; 

Each of the simple operators shown in Table 5-4 can be used in this manner.

Table 5-4. Shorthand operators

Operator	Shorthand	Equivalent statement
+=	x += 2;	x = x + 2;
-=	x -= 2;	x = x - 2;
*=	x *= 2;	x = x * 2;
/=	x /= 2;	x = x / 2;
%=	x %= 2;	x = x % 2;
++	++x;	x = x + 1;
--	-- x;	x = x - 1;

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