构造函数调用一次，析构函数为什么调用了两次？？？？？？？？？

#include<iostream>
#include<ctime>
#include<cstdlib>
using namespace std;
class Dice
{
public:
Dice()
{
cout<<"aaaaaaaa"<<endl;
}
~Dice()
{
cout<<"bbbbbbbb"<<endl;
}
int run()
{
return (rand()%6+1);
}
};
class Gambler
{
public:
Gambler()
{
cout<<"ccccccc"<<endl;
}
~Gambler()
{
cout<<"ddddddd"<<endl;
}
void play(Dice a,Dice b,Dice c)
{
int num1,num2,num3;
num1=a.run();
num2=b.run();
num3=c.run();
if(num1==num2&&num1==num3)
cout<<num1<<" "<<num2<<" "<<num3<<"豹子"<<endl;
else if (num1+num2+num3>10)
cout<<num1<<" "<<num2<<" "<<num3<<"大"<<endl;
else
cout<<num1<<" "<<num2<<" "<<num3<<"小"<<endl;
}
};
int main()
{
Dice a,b,c;
Gambler Jack;
srand(time(NULL));
Jack.play(a,b,c);
return 0;
}