C++封装例程(class,struct,public,protected,private,friend)

#if __cplusplus >= 201103L #include <cstdint> #else #include <stdint.h> #endif #include <cstring> #include <iostream> class Array { int32_t *array_; uint32_t size_; friend std::ostream & operator << (std::ostream &os, Array const& obj); public: Array(uint32_t n = 0) : array_(new int32_t[n]) , size_(n) { std::cout << "Array(int)" << std::endl; } Array(Array const& r)//拷贝构造函数 : size_(r.size_) , array_(new int32_t[size_]) { if(array_) memcpy(array_, r.array_, size_ * sizeof(int32_t)); std::cout << "Array(Array const&)" << std::endl; } Array& operator=(Array const& r)//赋值运算符 { if(this == &r) return *this; if(array_) delete []array_; size_ = r.size_; array_ = new int32_t[size_]; if(array_) memcpy(array_, r.array_, size_ * sizeof(int32_t)); std::cout << "operator=(Array const&)" << std::endl; return *this; } #if __cplusplus >= 201103L Array(Array && r) : array_(r.array_) , size_(r.size_) { r.array_ = nullptr; r.size_ = 0; std::cout << "Array(Array &&)" << std::endl; } Array& operator=(Array && r) { if(this == &r) return *this; if(array_) delete []array_; array_ = r.array_; size_ = r.size_; r.array_ = nullptr; r.size_ = 0; std::cout << "operator=(Array &&)" << std::endl; return *this; } #endif ~Array()//析构函数 { delete []array_; std::cout << " ~Array()" << std::endl; } uint32_t size() const { return size_; } bool setValue(uint32_t index, int32_t value) { if(index >= size_) return false; array_[index] = value; return true; } bool getValue(uint32_t index, int32_t& value) const { if(index >= size_) return false; value = array_[index]; return true; } }; std::ostream & operator << (std::ostream &os, Array const& obj) { for(uint32_t i = 0; i < obj.size_; i++) os << obj.array_[i] << " "; if(obj.size_ == 0) os << "empty"; os << std::endl; return os; } int main(int argc, char *argv[]) { Array array1(5); for(uint32_t i = 0; i < array1.size(); i++) array1.setValue(i, i + 1); Array array2 = array1; //拷贝构造函数 Array array3; array2.setValue(3, 10); array3 = array2;//赋值运算符 array3.setValue(5, 10); std::cout << "array1: " << array1 << "array2: " << array2 << "array3: " << array3; #if __cplusplus >= 201103L Array array4 = std::move(array3); Array array5; array5 = std::move(array2); std::cout << "array4: " << array4 << "array5: " << array5 << "array3: " << array3 << "array2: " << array2; #endif std::cout << "c++ version: " << __cplusplus <<std::endl; return 0; }