% DDBN file ddbn.m Step graph of distribution function
% Version of 10/25/95
% Plots step graph of dbn function FX from 
% distribution of simple rv (or simple approximation)
xc  = input('Enter row matrix of VALUES  ');
pc = input('Enter row matrix of PROBABILITIES  ');
m  = length(xc);
FX = cumsum(pc);
xt = [xc(1)-1-0.1*abs(xc(1)) xc xc(m)+1+0.1*abs(xc(m))];
FX = [0 FX 1];        % Artificial extension of range and domain
stairs(xt,FX)         % Plot of stairstep graph
hold on
plot(xt,FX,'o')       % Marks values at jump
hold off
grid                  
xlabel('t')
ylabel('u = F(t)')
title('Distribution Function')