Use c++ or matlab

Write a small program that loads in a text file of any size and then prints the frequency (as a percentage) of each character (a..z). All characters should be made lowercase for counting purposes. Ignore punctuation, spaces, etc. Output should be sorted in decreasing frequency order (e, t, a, o, etc.) and look something like: e 13.27% t 9.11% a 8.47% o 7.32% q 0.01% z 0.00%