function cdf = english_letter_cdf ( c ) %*****************************************************************************80 % %% ENGLISH_LETTER_CDF evaluates the English Letter CDF. % % Discussion: % % CDF('c') = 0.12441 % % Licensing: % % This code is distributed under the GNU LGPL license. % % Modified: % % 05 March 2016 % % Author: % % John Burkardt % % Reference: % % Robert Lewand, % Cryptological Mathematics, % Mathematics Association of America, 2000, % ISBN13: 978-0883857199 % % Parameters: % % Input, character C, the letter whose probability is desired. % 'a' <= c <= 'z', but case is ignored. % % Output, real CDF, the probability that a random letter is less % than or equal to C. % cdf_vec = [ ... 0.00000, ... 0.08167, 0.09659, 0.12441, 0.16694, 0.29396, ... 0.31624, 0.33639, 0.39733, 0.46699, 0.46852, ... 0.47624, 0.51649, 0.54055, 0.60804, 0.68311, ... 0.70240, 0.70335, 0.76322, 0.82649, 0.91705, ... 0.94463, 0.95441, 0.97802, 0.97952, 0.99926, ... 1.00000 ]; if ( 'a' <= c && c <= 'z' ) i = c - 'a' + 2; cdf = cdf_vec(i); elseif ( 'A' <= c && c <= 'Z' ) i = c - 'A' + 2; cdf = cdf_vec(i); else cdf = 0.0; end return end