#include<stdio.h>
#include<stdlib.h>
#include<math.h>
#include<math.h>

double Rosen (double x, double y)
{
    double z;
     z=100*(x-y*y)*(x-y*y)+(1-x*x)*(1-x*x);
 
    return z;
}

double grad1 (double x, double y)
{
    double z;
    z=200*(x-y*y)-4*x*(1-x*x);
   
    return z;
}

double grad2 (double x, double y)
{
    double z;
    z=-400*y*(x-y*y);
  
    return z;
}


int main ()
{
    double x,y,pom1,p1,p2,pom2,alfa,beta,pom3,b1,b2,xn,yn,r1,r2;
    int k, i, j;
    double (*f)(double x, double y);
    double (*g1)(double x, double y);
    double (*g2)(double x, double y);
    f=&Rosen;
    g1=&grad1;
    g2=&grad2;    
    
    x=0.25;
    y=0;
    p1=-(*g1)(x,y);
    p2=-(*g2)(x,y);
   
    k=0;
    pom1=1;
    while (pom1>0.0001)
    {

        b1=(196+8*x)*p1-400*y*p2;
        b2=-400*y*p1+1200*y*y*p2;
        pom3=b1*p1+b2*p2;
        alfa=-((*g1)(x,y)*p1+(*g2)(x,y)*p2)/pom3;
             
        pom2=(*g1)(x,y)*(*g1)(x,y)+(*g2)(x,y)*(*g2)(x,y);
        xn=x+alfa*p1;
        yn=y+alfa*p2;
         
        r1=((*g1)(xn,yn))*((*g1)(xn,yn)-(*g1)(x,y));
        r2=((*g1)(x,y))*((*g1)(x,y))+((*g2)(x,y))*((*g2)(x,y));
        beta=r1/r2;
      
        p1=-(*g1)(x,y)+beta*p1;
        p2=-(*g2)(x,y)+beta*p2;
        
        pom1=sqrt((*g1)(x,y)*(*g1)(x,y)+(*g2)(x,y)*(*g2)(x,y));
        x=xn;
        y=yn;
        k++;  
    }
    printf ("%f   %f\n", x, y);
    printf ("Broj iteracija: %d", k);
    
    return 0;
}