C programmimg of modified euler method?

Answer 1

#include <stdafx.h>

04#include "impeuler.h"

05

06double solveodimpeuler(double t, const double& tspan, double y, cont int& N, double tfinal)

07

08{

09 double result;

10 int i;

11 double h;

12

13 double f1;

14 double y1*;

15 double y1;

16

17 double f2;

18 double y2*;

19 double y2;

20

21 f1(t,y)=y2;

22 f2(t,y)=-4y1;

23 y=f1(t,y)+f2(t,y);

24

25 h= (tspan-t)/N;

26 y1(0)=0.01;

27 y2(0)=0.0;

28

29 tfinal=2pi/y;

30 N=tfinal/h;

31

32

33 i=1;

34 do

35 {

36 y1*(n+1)=y1(n)+h*y2(n);

37 y2*(n+1)=y2(n)+h*(-4y1(n));

38

39 y1(n+1)=y1(n)+(h/2)*[y2(n)+y2*(n+1)];

40 y2(n+1)=y2(n)+(h/2)*[-4y1(n)-4y1*(n+1)];

41 }

42 while(i<=N);

43 result=y;

44 return result;

45}