FY-3-a Best C++ program to add two complex number

#include<iostream>
using namespace std;
class complex
{
    int a,b;
    public:
        complex()
        {
            a=0;
            b=0;
        }
        complex(int m,int n)
        {
            a=m;
            b=n;
        }
        void show()
        {
            cout<<endl<<a;
            cout<<endl<<b;
        }
        complex sum(complex c1)
        {
            complex c3;
            c3.a=a+c1.a;
            c3.b=b+c1.b;
            return c3;
        }
};
int main()
{
    complex x(2,3);
    complex y(4,7);
    complex z;
    z=x.sum(y);
    cout<<"Values of first objects";
    x.show();
    cout<<endl<<"Values of second objects";
    y.show();
    cout<<endl<<"Result";
    z.show();
    return 0;
}