C++ Primer Plus

An Overloading Example

In this chapter we’ve already developed a left() function that returns a pointer to the first n characters in a string. Let’s add a second left() function, one that returns the first n digits in an integer. You can use it, for example, to examine the first three digits of a U.S. postal zip code stored as an integer, which is useful if you want to sort for urban areas.

The integer function is a bit more difficult to program than the string version because you don’t have the benefit of each digit being stored in its own array element. One approach is to first compute the number of digits in the number. Dividing a number by 10 lops off one digit, so you can use division to count digits. More precisely, you can do so with a ...