Program in C++ that read in a text file and outputs another different text file that

The letter/frequency pairs should be given in order of descending frequency. For example, the file should roughly look like this.

``` e, 0.082198 a, 0.050031 (etc) z, 0.003000

``` I have made up the values in the above table for the sake of example.

It is possible to implement this algorithm in a way that only makes one pass over the corpus. However, if you prefer to read through the file 27 times, that is feasible.

example

test.txt

THEETITLEISONE

outtest.txt

E,4

T,3

H,1

I,2

L,1

S,1

O,1

N,1