function mnhf_exchange_rate()
%MNHF_EXCHANGE_RATE plots then interpolates Canada-US exchange rate data.

ms = 10;  % markersize in figure.
fs = 12;  % fontsize in figure.

% Input exchange rate information. x represents the month of 2010; y gives
% the monthly average exchange rate (amount of US$ needed to buy $1 Cdn).
x = 1:1:12;
y = [0.95883 0.94623 0.97751 0.99496 0.96161 0.96345 0.95906 0.96026 ...
   0.96797 0.98234 0.98736 0.99231];

% Plot data.  
figure; hold on; box on
plot(x,y,'ko','markersize',ms)
set(gca,'fontsize',fs)
xlim([1 12])
set(gca,'xtick',[1 2 3 4 5 6 7 8 9 10 11 12])
set(gca,'xticklabel',['J';'F';'M';'A';'M';'J';'J';'A';'S';'O';'N';'D'])
xlabel('Month of 2010','fontsize',fs+4)
ylabel('Monthly average exchange rate','fontsize',fs+4)
title('Canada-US exchange rate','fontsize',fs+4)

% Contrast different interpolation routines.
xi = 1:0.05:12;
yi_nearest = interp1(x,y,xi,'nearest');
plot(xi,yi_nearest,'b-.')
yi_linear = interp1(x,y,xi,'linear');
plot(xi,yi_linear,'r--')
yi_spline = interp1(x,y,xi,'spline');
plot(xi,yi_spline,'k-')

% Add legend.
legend('Raw data','Nearest neighbor','Piecewise linear','Cubic spline',...
       'location','southeast')