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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
Templates with Default Type Parameters

It is possible to specify a default parameter type for a class template and starting from C++11, default template arguments can also be used in function templates. To set a default type, simply write the desired type after the equal sign for the template parameter.

main.cpp

main.cpp

copy

              
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#include <iostream>

template <typename T = int> // `int` will be used as a default type
class Box {
    T value; // Stores the value of type `T`
public:
    Box(T value) : value(value) { std::cout << this->value; } 
};

int main()
{
    // Type not specified
    // VV
    Box<> intBox(25.5);
}

When you run the code above, the output will be 25 instead of 25.5. This happens because the default type for the Box class is set to int, which truncates the decimal part of the value.

Note

Similar to default function arguments, if one template parameter has a default argument, then all template parameters following it must also have default arguments.

In addition to default type parameters, C++ allows for non-type template parameters with default values. Non-type parameters can be integral types, pointers, or references. To specify a non-type default parameter, you simply assign a default value after the parameter.

array.h

array.h

copy

              
123456

            
// `int` and `10` are default parameters
template <typename T = int, size_t Size = 10> 
struct Array
{
    T arr[Size]; // Array with a fixed size of `Size`
}

Default template parameters simplify code, reduce redundancy, and enable templates to handle typical use cases with minimal effort while allowing customization when needed.

question mark

When a template parameter has a default value, which of the following is true?

Select the correct answer

Var allt tydligt?

Hur kan vi förbättra det?

Tack för dina kommentarer!

Avsnitt 3. Kapitel 3

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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
Templates with Default Type Parameters

It is possible to specify a default parameter type for a class template and starting from C++11, default template arguments can also be used in function templates. To set a default type, simply write the desired type after the equal sign for the template parameter.

main.cpp

main.cpp

copy

              
123456789101112131415

            
#include <iostream>

template <typename T = int> // `int` will be used as a default type
class Box {
    T value; // Stores the value of type `T`
public:
    Box(T value) : value(value) { std::cout << this->value; } 
};

int main()
{
    // Type not specified
    // VV
    Box<> intBox(25.5);
}

When you run the code above, the output will be 25 instead of 25.5. This happens because the default type for the Box class is set to int, which truncates the decimal part of the value.

Note

Similar to default function arguments, if one template parameter has a default argument, then all template parameters following it must also have default arguments.

In addition to default type parameters, C++ allows for non-type template parameters with default values. Non-type parameters can be integral types, pointers, or references. To specify a non-type default parameter, you simply assign a default value after the parameter.

array.h

array.h

copy

              
123456

            
// `int` and `10` are default parameters
template <typename T = int, size_t Size = 10> 
struct Array
{
    T arr[Size]; // Array with a fixed size of `Size`
}

Default template parameters simplify code, reduce redundancy, and enable templates to handle typical use cases with minimal effort while allowing customization when needed.

question mark

When a template parameter has a default value, which of the following is true?

Select the correct answer

Var allt tydligt?

Hur kan vi förbättra det?

Tack för dina kommentarer!

Avsnitt 3. Kapitel 3
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