Computer Programming with C++

Overview

Templates in C++ are used to facilitate generic programming by giving the programmer an ability to create generic classes/functions in the program. A component of the program is said to be generic if its functionality remains the same irrespective of data type of the values it operates on. A generic function is a function that can work with arguments of any data type, whereas a generic class is a class that can work with members of any data type. In this chapter, we will learn creation of generic functions using function templates and creation of generic classes using class templates.

Function Templates

Function templates in C++ enable the programmer to create generic functions. These functions are adaptable to multiple data types and can execute in the same way immaterial of the data type of the values passed to it.

The functions we have written so far in the previous chapters are strictly bonded to specific types. For example, consider the function add() as shown below:

int add(int a,int b)

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int c = a+b;

return c;

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The function takes two arguments of type integer and returns the resultant integer, which gives addition of two numbers. This function works well if integer values are passed to it, however the function will not produce correct results if any other type of values are passed to it.

For instance, if we call the function add() by passing float values

float k = add(10.2,11.5);

the value returned in variable k will not be correct rather truncated. As per the default behaviour of C++, value in variable k will be 21.00 and not 21.7. This means that the function has performed truncation of the resultant value resulting in loss of data. And hence, the function cannot work for float type values.

At times, it is required to implement the same logic for multiple type of values. In such cases, you can use function templates in C++.