Here is my first own programme,i was trying to calculate error of finding roots for a second degree equation.I used float type for variables to see all result but i cant see results after some numbers.anyone can help this poor beginner with this?

Code:

#include <iostream>
#include <cmath>
using namespace std;
int main()
{
int i;
float p=1,X11,X12,E,Er;
for (i=0; i<10; i++)
{
p=p*10;
X11= -(p/2)- sqrt ((pow(p,2)/4)-1);
X12= 1 /((-(p/2)+sqrt ((pow(p,2)/4)-1)));
E= X11-X12;
Er= E/X11;
cout << "X^2-"<<p<<"x+1=0"<<endl;
cout <<"X11="<<X11<<'\t';
cout <<"X12="<<X12<<endl;
cout <<"E="<<E<<'\t'<<"Er="<<Er<<endl;
}
std::cout <<"Press [Enter] to continue" <<std::endl;
std::cin.get();
return 0;
}