function [t,y]=eulerprint(a,b,h,y0)
%function [t,y]=eulerprint(a,b,h,y0)
%Solution using Euler's Method.  Determines a solution y(t)
%  for t=a to t=b using step size h and initial condition y0.
%  To change the differential equation, go to the second to
%  last line- In the command window, type:  edit eulerprint.m
%
%This program will output a text file:  output.txt
%  containing columns of data from Euler's Method.
%
t=a:h:b;
n=length(t);
y=zeros(n,1);
dy=zeros(n-1,1);
y(1)=y0;

for i=2:n
    dy(i-1)=f(t(i-1),y(i-1));
    y(i)=y(i-1)+h*dy(i-1);
end

%These are the output file commands- No need to change these!
fid=fopen('output.txt','w');
fprintf(fid,'The first column is time, second is y, third is dy/dt\n');
for j=1:n
    if j<n
       fprintf(fid,'%f %f %f\n',t(j),y(j),dy(j));
    else
        fprintf(fid,'%f %f\n\n',t(j),y(j));
    end
end
fclose(fid);
%
%End of file output commands
%


%*********************************
function dy=f(t,y)
dy=1-t+4*y;
return