This assignment tests your ability to write C programs that handle keyboard input, formatted

console output, and input$/$output with text files. The program also tests your ability to write fairly

simple logic as well as use some of the ctype.h functions like isalpha and tolower. The

purpose of this program is to input a textfile and output select characters to a second textfile. Those

characters are the letters that fall between two letters input by the user, as well as punctuation and

whitespace $($note: whitespace is more than blank spaces$).$

After declaring your variables, input from the user two filenames $($for the input and output file

respectively$)$ and two letters. The filenames will be string variables $($no more than $20$ characters

are needed$)$ and they should be the only arrays you declare in this program. The first letter must

be less than the second letter $($they can either be upper or lower case$).$ Use data verification to

ensure both input characters are letters with the first being less than the second. Here is an example

of code you might use.

prompt the user

do $\{$

input both characters

$\}$while$(!$isalpha$($first$)||!$isalpha$($second$)||$

tolower$($first$)>$tolower$($second$))$;

To input chars, remember that the variable names need & $($as opposed to strings$)$ but also to input

chars, add a space before the $\%$c conversion character, as in scanf$("\%$c$",$ &first$)$; or

scanf$("\%$c $\%$c$",$ &first, &second$)$;

Open both files, the first as a read file and the second as a write file. The program will then input

the first file character$-$by$-$character using a while loop and output those letters that fall between the

two user$-$input letters $($inclusively$)$ along with all whitespace and punctuation marks but no digits.

All of this output goes to the second $($write$)$ file. As the input letters can be upper or lower case,

you will have to ensure that the current character is compared to these two properly. For instance,

if the letters input from the user are $$b$$ and $$p$$ and the current character is either $$d$$ or $$D$,$ it

should be output. Use toupper or tolower to compare first$/$second and the file$$s character.

While inputting and determining if a character is to be output, your program will also be required

to count each input character, each output character, and the number of letters that were not output

$($this last count doesn$$t include digits$).$ After exiting the while loop, close both files and compute

the difference in size between the output file and input file as a percentage using the formula

output$\_$size $/$ input$\_$size $*100.$ The variables input$\_$size and output$\_$size should be

ints and that would make the above division an int division requiring that you perform some kind

of casting to make one value a double $($without this, you will likely wind up with a value of $0\mathrm{.}0$

since input$\_$size $>$ output$\_$size$).$ Output a short report to the console window $($using printf

statements$)$ that lists the input file name, output file name, size of input file, size of output file,

number of letters not output, and percentage file change. See the example output on the next page

of this assignment. The output should be reasonably formatted with the numbers lining up$.$

There are two input files on the website. Download them and run your program on the first using

letters $$b$$ and $$p$($or $$B$$ and $$P$),$ comparing your results to the results below. Once your program

is properly debugged, run your program on the second input using $$e$$ and $$x$.$