clear; close all
%
%  Lab 4
%  Exercise the Collatz function and plot the results
%
myname = 'Warren Gibson'; ID = 123456;
%
%  Pick a random odd starting number.  Generate and plot the sequence.
%
n = 20*mod(ID,10)+1;
c = collatz(n);
semilogy(c,'*-')
xlabel('Iteration')
ylabel('Sequence value')
header = sprintf('Collatz history for starting value n = %d by %s, ID %d', ...
                                n,myname,ID);
title(header)
start =      ;  %% vector of starting numbers 3,5, ... 100,000
nstart = length(start);
nmax = zeros(1,nstart);  %% Pre-allocate arrays
nit = zeros(1,nstart);
%
%  Repeat for each starting number
%  Get nmax and nit for each starting number
%
for i=1:nstart
    c = collatz(start(i));
    if isinf(c(end)) %% did we overflow?
        fprintf('Overflow for n=%d\n',start(i))
        break
    end
    nmax(i) = 
    nit(i) = 
end
figure
loglog(start,nit,'.');
xlabel('Starting number');
ylabel('Iterations to finish');
header = sprintf('Collatz problem, %s, ID %d',myname,ID);
title(header)

figure; %% Now plot highest number reached vs. starting number
loglog(
etc.