Motivation for using templates

So far, when we have defined a function or a class, we have had to provide input, output, and intermediate parameters. For example, let’s say we have a function to perform the addition of two int-type integers. How do we extend this so that it handles all the other basic data types, such as float, double, char, and so on? One way is to use function overloading by manually copying, pasting, and slightly modifying each function. Another way is to define a macro to do the addition operation. Both approaches have their side effects.

Moreover, what happens if we fix a bug or add a new feature for one type, and this update needs to be done for all the other overloading functions and classes later? Instead of using this silly copy-paste-and-replacement method, do we have a better way of handling this kind of situation?

In fact, this is a generic problem that any computer language can face. Pioneered by the general-purpose functional programming...