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Implement Template

2025-12-15

Software Development with C and Cpp

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template <typename T> class Area {
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public:
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    void setLength(T newValue);
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protected:
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    T length;
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};

1. Implementing the template method `setLength()`#

For class templates, method implementations must also be templated and usually placed in the header file.

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template <typename T>
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void Area<T>::setLength(T newValue) {
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    length = newValue;
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}

2. Implementing two different template methods to calculate the area of a square#

We can interpret “two different template methods” in two common, correct ways:

Option 1: Two methods with different return types / purposes#

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template <typename T>
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class Area {
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public:
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    void setLength(T newValue);
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    T getArea() const;           // returns area
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    void printArea() const;      // prints area
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protected:
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    T length;
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};

Implementations:

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template <typename T>
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T Area<T>::getArea() const {
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    return length * length;
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}
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template <typename T>
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void Area<T>::printArea() const {
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    std::cout << length * length << std::endl;
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}

Option 2: Method template specialization using different numeric types#

If “two different template methods” means overloading for different types:

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template <typename T>
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class Area {
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public:
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    void setLength(T newValue);
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    T area() const;
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};

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template <typename T>
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T Area<T>::area() const {
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    return length * length;
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}

Then specialize if needed (example):

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template <>
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double Area<double>::area() const {
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    return length * length;
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}

Complete Minimal Example#

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#include <iostream>
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using namespace std;
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template <typename T>
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class Area {
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public:
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    void setLength(T newValue);
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    T getArea() const;
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protected:
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    T length;
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};
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template <typename T>
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void Area<T>::setLength(T newValue) {
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    length = newValue;
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}
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template <typename T>
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T Area<T>::getArea() const {
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    return length * length;
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}

Exam-Friendly Summary#

Template member functions must be implemented using template<typename T> return_type Class<T>::function(...)
Area of a square is computed as length * length
Template methods are usually implemented in header files

Implement Template

https://mizuki.anka2.top/posts/l5-cpp-week12-lecture/implement-template/

作者

🐦‍🔥不死鸟Anka

发布于

2025-12-15

许可协议

MIT