Question

Display 7.10 shows a function called search, which searches an array for a specified integer. Give a function template version of search that can be used to search an array of elements of any type. Give both the function declaration and the function definition for the template. Hint: It is almost identical to the function given in Display 7.10

Short answer

In the given solution, a function template for the search function is created using a generic type 'T'. The function can search for a specified element of any data type in an array. The main steps in creating the function template include: 1. Replacing the specific data type with a template type 'T' and adding "template" to the function declaration and definition. 2. Modifying the function declaration for the template version by adding the template keyword and the generic data type 'T'. 3. Modifying the function definition for the template version by adding the template keyword and replacing the specific data type with the generic data type 'T'. Following these steps, the search function can now operate on an array containing elements of any data type, not just integers.

Step-by-step solution

Replace the specific data type with a template type

Replace the data type of the "search" function, such as 'int', with a generic type named 'T' and prepend "template" to the function declaration and definition.

Modify the function declaration of the template

Modify the function declaration by adding the template keyword and the generic data type 'T'. This tells the compiler that the following function is a template function and will take a generic type 'T' as input.

Modify the function definition of the template

Modify the function definition for the template version by adding the template keyword, and replace the specific data type with the generic data type 'T'. Here's the function declaration and the function definition for the search function template: ```cpp // Function declaration template int search(const T list[], int size, T searchTerm); // Function definition template int search(const T list[], int size, T searchTerm){ for(int i = 0; i < size; i++){ if(list[i] == searchTerm){ return i; } } return -1; } ``` Now, the 'search' function can be used to search an array for an element of any type, not just integers.

Key concepts

Generic Programming

Generic programming in C++ is a programming approach that enables functions or classes to work with different data types without being rewritten for each one. This is achieved through the use of templates, which are a powerful feature of C++ that allow you to write code that is independent of any specific type. Generic programming is particularly useful for writing libraries and reusable code, because it allows the same piece of code to operate on a variety of data types.

When you create a generic function or class, you don't initially specify the exact data type it will work with. Instead, you use placeholders, typically called type parameters or template parameters, which will be replaced with actual data types when the function or class is instantiated. This leads to less redundancy and more versatile code. For example, the 'search' function in the textbook problem uses a template to allow searching through an array of any type, where the type 'T' stands as a placeholder for any data type.

C++ Templates

C++ templates are the foundation of generic programming in C++. They allow you to define functions, classes, and even methods that are not tied to a specific data type. When you declare a template, you use the keyword 'template' followed by a template parameter list enclosed in angle brackets. This parameter list usually includes one or more type parameters, represented as 'typename T' or 'class T'.

The beauty of templates is that they enable type-safe code reusability. A single template can cater to many data types, as long as the operations within the template are valid for those types. In the given textbook solution, a function template for 'search' is defined, which allows it to be used with any array type, not just integers. It's crucial to provide both a template declaration and a template definition to ensure the compiler knows how to instantiate the template for different types. Templates are compiled when called, and the compiler generates code for the specific instantiation, which would be a specific data type in the case of the 'search' function.

Algorithm Implementation

Understanding Algorithm Implementation with Templates

Implementing algorithms in C++ using templates is a strategy that can greatly enhance code reusability and efficiency. An algorithm describes a step-by-step procedure for solving a problem or performing a task. By implementing algorithms with templates, you ensure that your code can handle a variety of data types and structures without needing multiple versions of the same algorithm.

To implement an algorithm as a template, as in the 'search' function example, you begin by identifying operations within the algorithm that are dependent on the data type. Next, you replace the data type-dependent parts with template parameters, which makes the algorithm generic. The template's type parameters are then replaced with actual types at compile time, depending on the context in which the algorithm is used.

This process showcases the elegance of generic programming - one algorithm fits all. By using a template for the 'search' function, any array type can be used just as efficiently as if there were a specific function for each type. It also demonstrates how templates are a powerful tool for implementing algorithms that are not only generic but also type safe and efficient.