#include
#include

double kula(double t,double v);
double rk4( double x0, double y0, double h, double (*fun)(double, double));

double g,m,c,v0;

void main()
{double t,v,dt,tk;
g=9.81;m=2.;c=.003;v0=50.;


printf("podaj dt i tk\n");
scanf("%lf%lf",&dt,&tk);
//wp
t=.0;
v=v0;
//całkujemy
while(t<=tk)
{
v=rk4(t,v,dt,kula);
t=t+dt;
}
}
double kula(double t,double v)
{double f;
f=g-c/m+v*v;
return f;
}
double rk4( double x0, double y0, double h, double (*fun)(double, double))
{
double y1;
double k1,k2,k3,k4;
k1 = h*fun(x0 ,y0 );
k2 = h*fun(x0+h/2.,y0+k1/2.);
k3 = h*fun(x0+h/2.,y0+k2/2.);
k4 = h*fun(x0+h ,y0+k3 );
y1 = y0 + (k1+2.*k2+2.*k3+k4)/6.;
return y1;
}