написанные программы / метод прогноза и коррекции / ChZ3

#include<conio.h>
#include<iostream.h>
#include<math.h>
#include<stdlib.h>

#define fun cos (x) - sin (x) - y
#define prec 0.00001
#define xm 0.0
#define ym 2.0
#define h 0.5
#define n 20


double func(double x)
{
	return cos(x)+exp(-x);
}


double f(double x,double y)
{
	return fun;
}


double Eiler ()
{
	return
	 (ym+h*f(xm+h/2,ym+h/2*f(xm, ym)));
}


double *function ()
{
	double *mas, a;

	mas =(double*)malloc(sizeof (double) *n);
	mas[0] =ym;mas[1] =Eiler ();

	for (int i=2;i<n;i++)
	{
		a=mas[i-2]+2.0*h*f(xm+h*(i-1),mas[i-1]);
		mas[i]=mas[i-1] + h * 0.5 * (f (xm+h*(i-1),mas[i-1]) + f (xm+h*i,a));

		while (fabs(a-mas[i])>prec)
		{
			a=mas[i];
			mas[i]=mas[i-1] +
			 h*0.5*(f(xm+h*(i-1),mas[i-1])+f(xm+h*i,a));
		}
	}

	return mas;
}


void main()
{
	clrscr();

	double *mas=function ();

	cout<<"----Xm---|-----Ym-----|-----Y(p&k)-----|"<<endl;
	for (int i=0;i<n;i++)
	  cout <<"   "<< xm + h * i <<"       " << func (xm + h * i) <<"      " <<mas[i]<<endl;

	delete mas;

	getch ();
}