const成员函数调用的区别！
代码如下：
#include <string>#include <iostream>using namespace std;class Sales_item{ public: int func(Sales_item &si)const; int func(Sales_item &si); Sales_item():ival(1){ } private: int ival;};int Sales_item::func(Sales_item &si)const{ return ival;}int Sales_item::func(Sales_item &si){ ival=10; return ival;}int main(){ Sales_item si1; cout<<si1.func(si1)<<endl;//非const对象调用非const函数 const Sales_item si2; cout<<si2.func(si1)<<endl;//const对象调用const函数 system("pause"); return 0;}