What a template is

Templates are a relatively new concept in computer languages. A template is a soft-ware engineering tool that enables a programmer to reuse code on many different datatypes. 

The best way to describe a template is as a pattern, or a mold, which will be reused over and over again. A real-world example would be the procedures of a company that manufactures figurines. First, the company produces a mold of the figure they want to produce. After that, they choose which material they want the figures made of, and then they use the mold to create the figure. With the same mold, they can make a figure out of plastic, pewter, iron, or even gold and silver.A template in C++ is basically the same concept. A template is a mold for an algorithm or a class, and the programmers decide what type of material they want to use with it. This is a tremendously powerful tool, as you can see, because you can make a generic algorithm or a class that will theoretically operate on hundreds of different datatypes. The main advantage of using a template is that it allows you to stop copying and pasting code that operates on a specific datatype and changing it to a different datatype.

Say you want a specific algorithm to work on six different types of datatypes. Without templates, you would have to copy and paste the algorithm six times and manually change the datatypes in each copy! With templates, it is possible to make only one copy of the code and use that one copy over and over again. The algorithm on the right-hand side of Figure  is your mold, which allows you to make figurines of any type you want.