Write C++ program is used for finding the real root of an equation by Newton Raphson technique

#include <iostream.h> 
  #include <math.h> 
  #include<conio.h> 
  const double acc = 0.00000000001; 
  float r1, r, er; 
  inline float s(float x) 
     { 
            return (x * x + 2 * x + 1); 
      } 
  inline float ds(float x) 
     { 
           return (2 * x + 2); 
     } 
  void main() 
 {       clrscr(); 
         cout<<"Enter the initial value of root "; 
         cin>>r; 
         er = 2; 
         while(er>acc) 
            { 
               if(ds(r) == 0) 
                 goto l1; 
                   r1 = r - (s(r)/ds(r)); 
                  er = fabs(r - r1); 
                  r = r1; 
             } 
                  l1: 
                                cout<<" A real root is "<<r<<"\n"; 
                                getch(); 
 }