Templates in C++

Templates are considered simple yet powerful tools in C++. They work on a simple idea of passing a data type as a parameter. This helps programmers from writing the same code of different data types. For example, a renowned software company may contract you to create sort () for various data types. Instead of writing and maintaining multiple codes, you can write one sort () and pass data types as a parameter.

To support templates, C++ has two new keywords, namely ‘template’ and ‘typename.’ The keyword class can always be used to replace the second keyword – ‘typename.’

Like in macros, templates in C++ are expanded at compiler time. The only difference is that in C++, the compiler does type checking before performing template expansion. The idea here is the source code has only the function/class, while the compiled code may have several copies of the same function/class. The diagram below explains it better:

These are generic functions that can be used for different data types. Common examples of function templates are max(), min(), sort(), and printArray()

To declare a function template, start with the keyword template followed by the template parameter. The parameter should be inside the <>. This is then followed by the function declaration. Check out the example below:

Template < class T>

T ourFunction (T arg)

{

. . . .. . . . . . .

}

Example 1

Write a C++ program that implements the bubble sort using templates.

// CPP code that implements bubble sort using the template function

#include

Using namespace std;

//a template function that implement bubble sort

//it can be used for any data type that supports comparison operator < and swap works for it

Template

Void bubble sort (T a[], int n) {

for (int k = 0; k < n-1; k ++)