#include <iostream>

using namespace std;


int CheckTax(const double Income, double &Tax);


class SaleInf

{

public:

SaleInf(const double Income);

double GetTax();


private:

double Income;

double Tax;

};


SaleInf::SaleInf(const double Income)

{

this -> Income = Income;

}


double SaleInf::GetTax()

{

CheckTax(Income, Tax);


return Tax;

}


int CheckTax(const double Income, double &Tax)

{

if(Income <= 0)

return 0;


Tax = 0.03 * Income;

return 10;

}


int main()

{

SaleInf s1(20.4);

cout << "세금 : " << s1.GetTax() << endl;


double income = 20.4, tax;

CheckTax(income, tax);


cout << "세금 : " << tax << endl;


return 0;

}



c++ 배운지 얼마안됐는데요... 4번째줄에 int CheckTax(const double Income, double &Tax); 에서


&Tax에서 왜 &붙이는지 이해가 안되요 실제로 없이 실행시키니깐 이상한값나오긴 하는데 이유를 잘모르겠어요 ㅠㅠ