C++ 学习之路(3)：向函数传递对象

// 向函数传递对象
#include <iostream>
using namespace std;
class aClass
{
public:
aClass(int n)
{ i = n; }
void set(int n)
{ i = n; }
int get()
{ return i; }
private:
int i;
};
// 对象作为函数的参数(传值)
void sqr1(aClass ob)
{
ob.set(ob.get()*ob.get());
cout<<"Copy of obj has i value of ";
cout<<ob.get()<<endl;
}
// 对象指针作为函数的参数(传址)
void sqr2(aClass *ob)
{
ob->set(ob->get()*ob->get());
cout<<"Copy of obj has i value of ";
cout<<ob->get()<<endl;
}
// 对象的引用作为函数的参数
void sqr3(aClass &ob)
{
ob.set(ob.get()*ob.get());
cout<<"Copy of obj has i value of ";
cout<<ob.get()<<endl;
}

int main()
{
aClass obj(10);

cout<<"----对象 作函数参数----"<<endl;
sqr1(obj);
cout<<"But, obj.i is unchanged in main:";
cout<<obj.get()<<endl;

cout<<"----对象指针 作函数参数----"<<endl;
sqr2(&obj);
cout<<"Now, obj.i in main() has been changed. :";
cout<<obj.get()<<endl;

cout<<"----对象的引用 作函数参数----"<<endl;
// 上面操作已将对象obj的数据成员i改变，此处改回。
obj.set(10);

sqr3(obj);
cout<<"Now, obj.i in main() has been changed. :";
cout<<obj.get()<<endl;

return 0;
}