基礎C++ functional

　　函數對象：可以定義函數對象。

sort(this->sprites.begin(), this->sprites.end(), [](const struct SpriteInfo & s1, const struct SpriteInfo & s2) {
        return s1.priority > s2.priority;
    });


typedef function<void (string &)> callback;
void func(string &data)
{
    data = "YES";
    cout << data << endl;
}
void callee(string &data, callback call)
{
    call(data);
}
int main()
{
    string data;
    //callback call = &(func);
    //callee(data, call);
    callback call = [] (string data) { cout << "YES" << endl; };
    call(data);
    return 0;
}