如今,大多软件将界面和业务逻辑进行分离,达到一个松耦合的效果。但由于思考出发点不同将会发生如下问题:
界面显示5条格式类似的数据,于是,界面侧设计了如下结构用于存储此5条数据:
struct Screen { int line1; int line2; int line3; int line4; int line5; };
于是,业务逻辑层只能通过如下方法进行设置:
Screen screen; screen.line1 = 1; screen.line2 = 2; screen.line3 = 3; ... setScreen(screen);
实际每一行的数据顺序地进行存储,从而顺序读出,所以业务逻辑层希望写出如下代码:
for(int i = 0; i < 5; ++i) { screen.line[i] = getLine(i); }
由于UI层设计的结构并非采用数组结构,不能进行循环,于是,我们便在业务层中将其转化为数组,小小利用下成员指征便可完成上述想法。
#include <iostream> struct Screen { int line1; int line2; int line3; int line4; int line5; }; typedef int Screen::*Screen_Line; int getLine(int line) { return line; } int main() { //重映射成员指针数组 Screen_Line memArray[5] = { &Screen::line1, &Screen::line2, &Screen::line3, &Screen::line4, &Screen::line5, }; Screen testStruct; //下面即可采用循环进行设置 for (int i = 0; i < 5; ++i) { testStruct.*memArray[i] = getLine(i); } std::cout << "Screen::line1 : " << testStruct.line1 << std::endl; std::cout << "Screen::line2 : " << testStruct.line2 << std::endl; std::cout << "Screen::line3 : " << testStruct.line3 << std::endl; std::cout << "Screen::line4 : " << testStruct.line4 << std::endl; std::cout << "Screen::line5 : " << testStruct.line5 << std::endl; return 0; }