C++ Primer Plus

Choosing an Integer Type

With the richness of C++ integer types, which should you use? Generally, int is set to the most “natural” integer size for the target computer. Natural size refers to the integer form that the computer handles most efficiently. If there is no compelling reason to choose another type, you should use int.

Now look at reasons why you might use another type. If a variable represents something that is never negative, such as the number of words in a document, you can use an unsigned type; that way the variable can represent higher values.

If you know that the variable might have to represent integer values too great for a 16-bit integer, you should use long. This is true even if int is 32 bits on your system. That way, if ...