#include <iostream>
#include <cstring>
#include <cstdlib>

using namespace std;

template <typename T>
T &maxVal(T &a, T &b)
{
    return a > b ? a : b;
}

class A
{
private:
    int x;

public:
    A(int x) : x(x) {}
    void show()
    {
        cout << "x = " << x << endl;
    }

public:
    // 重载运算符>，解决函数模版的局限性，不用具体化函数模版
    bool operator>(const A &a) const
    {
        return this->x > a.x;
    }
};

int main()
{
    A a1(20), a2(50);
    // A &b = maxVal<A>(a1, a2);
    A &b = maxVal(a1, a2);
    b.show();
    return 0;
}