Constructors ques 3

#include<conio.h>
#include<iostream.h>
class fib
{ int first,sec,n;
 public:
fib()
{ first=0;
sec=1;
n=10;
}
fib(int a,int b,int c)
{ first=a;
sec=b;
n=c;
}
 void gen_fib();
 };
 void fib::gen_fib()
{ int a,b,c;
a=first;
b=sec;
cout<<a<<" "<<b<<" ";
for(int i=0;i<n-2;i++)
{ c=a+b;
a=b;
b=c;
cout<<c<<" ";
}
cout<<endl;
}
 void main()
 { clrscr();
int a,b,c;
fib a1;
cout<<"enter first sec and no. of terms";
cin>>a>>b>>c;
fib a2(a,b,c);
cout<<"default fibonacci series";
a1.gen_fib();
cout<<"user fibonacci series";
a2.gen_fib();
getch();
 }