Bài tập về số phức

#include<stdio.h>
#include<conio.h>
class Complex
{
public:
Complex (int th=0,int a=0) //constructor
{
thuc=th;
ao=a;
}
void Print() //ham xuat so phuc
{
if(thuc==0)
{
printf("%di",ao);
}
else
{
if(ao>0)
{
printf("%d+%di",thuc,ao);
}
else if(ao<0) printf("%d%di",thuc,ao);
else printf("%d",thuc);
}
}
// dinh nghia toan tu chong
friend Complex operator*(const Complex& x,const Complex& y);
friend Complex operator+(const Complex& x,const Complex& y);
friend Complex operator-(const Complex& x,const Complex& y);
private:

int thuc,ao;
};
//cai dat toan tu chong
Complex operator*(const Complex& x,const Complex& y)
{
Complex z(x.thuc*y.thuc-x.ao*y.ao,x.ao*y.thuc+x.thuc*y.ao);
return z;
}
Complex operator+(const Complex& x,const Complex& y)
{
Complex z(x.thuc+y.thuc,x.ao+y.ao);
return z;
}
Complex operator-(const Complex& x,const Complex& y)
{
Complex z(x.thuc+y.thuc,-x.ao-y.ao);
return z;
}
int main()
{
Complex x(0,-3),y(4,5);
x.Print();printf("\n");
y.Print();printf("\n");
Complex z;
z=x+y; //tinh tong
z.Print();printf("\n");
z=x-y; //tinh tong
z.Print();printf("\n");
z=x*y; //tinh tich
z.Print();printf("\n");

getch();
return 0;
}