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C++ Templates
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Kursinnehåll

C++ Templates

C++ Templates

1. Creating First Template
Introduction to C++ TemplatesBasic Syntax of Templates in C++Creating Your First Template in C++Working with Multiple Typenames in TemplatesNaming Conventions
2. Templates Usage
Typename Parameter as a Return TypeImplicit and Explicit Type SpecificationNon-type Template Parameters
3. Class Templates
Introduction to Class templatesTemplate Classes and STLTemplates with Default Type ParametersClass Template Argument Deduction
4. Template Specialization
Introduction to Template SpecializationHow to Use Template SpecializationPartial Template SpecializationTemplate ConstraintsOverview

book
Basic Syntax of Templates in C++

Creating a template is actually quite simple, and it's one of the easiest parts of using them. To start, you'll need to create either a function or a class. We will start with the function.

main.cpp

main.cpp

copy

              
123456

            
void MyFirstTemplate() { }

int main()
{
	MyFirstTemplate();
}

As you can see, there is a very simple function that does nothing for now. We can easily call it inside the main function. Your task now is to turn it into a template.

template.h

template.h

copy

              
123456789101112

            
// To create a template, you need to add code above the function or class
// Start with the keyword `template` to indicate you're defining a template
//                             template
  
// Add angle brackets `<>`, this is list of the parameters for template
//                           template < >
  
// Inside of it has to be keyword `typename` and the name of it
//                      template <typename Name>

template <typename Name>
void MyFirstTemplate() { }

Now, let's make it do something, like printing a message. Go ahead and call it inside the main function to see it in action.

main.cpp

main.cpp

copy

              
123456789101112

            
#include <iostream>

template<typename Name>
void MyFirstTemplate()
{ 
    std::cout << "c<>definity" << std::endl;
}

int main()
{
    MyFirstTemplate();
}

As you can see, an error arises when we try to call it as if it were a simple function. This is because it's no longer just a simple function. This is where the template parameter, specified inside the brackets after the keyword template, comes into play.

main.cpp

main.cpp

copy

              
12345678910111213

            
#include <iostream>

// This essentioally creates an alias for a type we will use
template<typename Name> // In our case the name of the type is Name
void MyFirstTemplate() { std::cout << "c<>definity" << std::endl; }

int main()
{
    // In order to call the template function properly 
	// We need to specify any type inside the brackets
    MyFirstTemplate<void>();
    // This tells the template to use void as the type for Name
}

Note

It doesn't matter what type you specify for this example, so you can change void to any type you want. However, specifying the type is mandatory.

For the MyFirstTemplate function template, it is not necessary to specify a name for the type parameter. You can remove Name, and everything will still work because the type parameter is not used inside the function.

question mark

What is the correct syntax for declaring a template function?

Select the correct answer

Var allt tydligt?

Hur kan vi förbättra det?

Tack för dina kommentarer!

Avsnitt 1. Kapitel 2

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course content

Kursinnehåll

C++ Templates

C++ Templates

1. Creating First Template
Introduction to C++ TemplatesBasic Syntax of Templates in C++Creating Your First Template in C++Working with Multiple Typenames in TemplatesNaming Conventions
2. Templates Usage
Typename Parameter as a Return TypeImplicit and Explicit Type SpecificationNon-type Template Parameters
3. Class Templates
Introduction to Class templatesTemplate Classes and STLTemplates with Default Type ParametersClass Template Argument Deduction
4. Template Specialization
Introduction to Template SpecializationHow to Use Template SpecializationPartial Template SpecializationTemplate ConstraintsOverview

book
Basic Syntax of Templates in C++

Creating a template is actually quite simple, and it's one of the easiest parts of using them. To start, you'll need to create either a function or a class. We will start with the function.

main.cpp

main.cpp

copy

              
123456

            
void MyFirstTemplate() { }

int main()
{
	MyFirstTemplate();
}

As you can see, there is a very simple function that does nothing for now. We can easily call it inside the main function. Your task now is to turn it into a template.

template.h

template.h

copy

              
123456789101112

            
// To create a template, you need to add code above the function or class
// Start with the keyword `template` to indicate you're defining a template
//                             template
  
// Add angle brackets `<>`, this is list of the parameters for template
//                           template < >
  
// Inside of it has to be keyword `typename` and the name of it
//                      template <typename Name>

template <typename Name>
void MyFirstTemplate() { }

Now, let's make it do something, like printing a message. Go ahead and call it inside the main function to see it in action.

main.cpp

main.cpp

copy

              
123456789101112

            
#include <iostream>

template<typename Name>
void MyFirstTemplate()
{ 
    std::cout << "c<>definity" << std::endl;
}

int main()
{
    MyFirstTemplate();
}

As you can see, an error arises when we try to call it as if it were a simple function. This is because it's no longer just a simple function. This is where the template parameter, specified inside the brackets after the keyword template, comes into play.

main.cpp

main.cpp

copy

              
12345678910111213

            
#include <iostream>

// This essentioally creates an alias for a type we will use
template<typename Name> // In our case the name of the type is Name
void MyFirstTemplate() { std::cout << "c<>definity" << std::endl; }

int main()
{
    // In order to call the template function properly 
	// We need to specify any type inside the brackets
    MyFirstTemplate<void>();
    // This tells the template to use void as the type for Name
}

Note

It doesn't matter what type you specify for this example, so you can change void to any type you want. However, specifying the type is mandatory.

For the MyFirstTemplate function template, it is not necessary to specify a name for the type parameter. You can remove Name, and everything will still work because the type parameter is not used inside the function.

question mark

What is the correct syntax for declaring a template function?

Select the correct answer

Var allt tydligt?

Hur kan vi förbättra det?

Tack för dina kommentarer!

Avsnitt 1. Kapitel 2
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