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重载操作符

2024-07-18 03:36:25   228人阅读

C++语法规定可以重载操作符，例如*和->。下面是一个例子：

class Screen{public:    Screen(int x, int y)    {        m_x = x;        m_y = y;    }    int m_x;    int m_y;};template<class TYPE>class ThreadLocal{public:    ThreadLocal(TYPE &s)    {        ptr = &s;    }    TYPE& operator*() {    return *ptr; }    TYPE* operator->() { return ptr; }private:    TYPE *ptr;};int main(int argc, char* argv[]){    Screen s1(100, 60);    ThreadLocal<Screen> ps(s1);    printf("%d, %d\n%d, %d\n", (*ps).m_x, (*ps).m_y, ps->m_x, ps->m_y);    return 0;}

重载操作符很容易与转换函数混淆，例如下面的例子：

class Screen{public:    Screen(int x, int y)    {        m_x = x;        m_y = y;    }    int m_x;    int m_y;};template<class TYPE>class ThreadLocal{public:    ThreadLocal(TYPE &s)    {        ptr = &s;    }    operator TYPE*() { return ptr; }    TYPE* operator->() { return ptr; }private:    TYPE *ptr;};int main(int argc, char* argv[]){    Screen s1(100, 60);    ThreadLocal<Screen> ps(s1);    printf("%d, %d\n%d, %d\n", (*ps).m_x, (*ps).m_y, ps->m_x, ps->m_y);    return 0;}

 


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