浪费大神一点点时间（大概1分钟），帮忙找出这个小程序的错误~

#include <iostream>
#include <math.h>
using namespace std;
class Score
{
private:
float c;
public:
Score(){c=0;}
Score(float a)
{
c=a;
}
float get_s()
{
return c;
}
Score operator+ (Score &c1);
Score operator/ (int &c1);
};
Score Score::operator+(Score &c1)
{
Score c2;
c2.c=c+c1.c;
return c2;
}
Score Score::operator /(int &c1)
{
Score c2;
c2.c=c/c1;
return c2;
}
int main()
{
Score Math(80),Chinese(75),English(85);
Score total= Math+Chinese+English;
Score average = total/3;
std::cout<<total.get_s()<<std::endl;
std::cout<<average.get_s()<<std::endl;
return 0;
}