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C function pointers are used to implement strategy mode, command mode and observer mode in design mode, providing the ability to dynamically select and switch behaviors at runtime, thereby enhancing the flexibility, reusability and scalability of the code sex. The specific functions are as follows: Strategy mode: store and switch different algorithms. Command mode: wraps and executes different commands. Observer pattern: maintain a list of observers and trigger callbacks.
C Function pointer: a powerful assistant in design patterns
Introduction
A C function pointer is a special type that points to a function and provides the ability to call functions indirectly. In design patterns, function pointers can play an important role in enhancing code flexibility, scalability, and decoupling.
The role of function pointers
The role of function pointers in design patterns is mainly reflected in the following aspects:
Practical Case: Strategy Pattern
Consider the following example of Strategy Pattern:
class SortStrategy { public: virtual void sort(vector<int>& data) = 0; }; class BubbleSort : public SortStrategy { public: void sort(vector<int>& data) override { for (int i = 0; i < data.size() - 1; i++) { for (int j = 0; j < data.size() - i - 1; j++) { if (data[j] > data[j + 1]) { swap(data[j], data[j + 1]); } } } } }; class QuickSort : public SortStrategy { public: void sort(vector<int>& data) override { // ... } }; class SortContext { public: SortContext(SortStrategy* strategy) : strategy_(strategy) {} void sort(vector<int>& data) { strategy_->sort(data); } private: SortStrategy* strategy_; };
In the above code, SortStrategy
is an abstract base class that defines the interface of the sorting algorithm. BubbleSort
and QuickSort
are specific strategy classes that implement different sorting algorithms. The SortContext
class uses a function pointer to store the sorting strategy and call the sorting method through it.
In this way, client code can dynamically select and replace sorting algorithms as needed without modifying the implementation of the SortContext
class.
Conclusion
C Function pointers play a key role in design patterns, they provide the ability to dynamically select and switch behaviors at runtime. By using function pointers, you can increase the flexibility, reusability, and extensibility of your code.
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