c++常量成员函数

#include <iostream>
using namespace std;

class MyClass {
int x;
public:
MyClass (int val) : x (val) {}
const int& get () const {return x;}
};

void print (const MyClass& arg) {
cout << arg.get() << endl;
}

int main () {
MyClass foo (10);
print (foo);
return 0;
}