Name: Anastasia Belenkii
Course: COMSC-110-1021

1. Objective: Extract email addresses from a file and output them to console

2. Requirements
INPUT:
iFile
keepGoing
enterKey
oFile
line

PROCESSING:(list of the major parts of the objective [that will become the code blocks in a program])
1. introduction and directions
2. get input and output files from user, output filenames back to user and wait for confirmation before proceeding
3. open input file, search for valid email addresses, if not duplicate then output them and add to list

OUTPUT:
dFile
prompt1
prompt2
label1
iFile
label2
oFile
prompt3
anEmail
emptymsg
size of list email
nonevalidmsg
goodbyemsg

DATA: (name of data item, definition, data type, valid values...)
iFile-> name of input file [string] [any string]
dFile->default filename for input or output [string] ["fileContainingEmails.txt", iFile, or "copyPasteMyEmails.txt"]
oFile-> name of output file [string] [any string]
enterKey-> whether the enter key was pressed at a prompt or not [true/false]
keepGoing-> input to determine whether program was unpaused or not [string] [any string]
line-> each line of the input file [string] [any string]
i-> loop index for going over each character in line [whole number] [any whole number greater than 0]
empty->whether the input FILE has '@'s or not [true/false]
hasDot = false; //whether the substring(subset of string) has a dot or not [true/false]
s->the index for going to the start of the substring [whole number] [any whole number that is at most 1 less than i]
e->the index for going to the end of the substring [whole number] [any whole number that is at least 1 + i]
anEmail->an email that has been detected [string] [any string composed of valid email characters, with a dot that at least one character between it and an @]
dotPos->position of dot [whole number] [any whole number greater than 0]
is->whether a given character is a valid email character
email->list of emails [list of strings] [members must be valid emails, no duplicates]
m->
n->
temp->

prompt1: "Please enter the name of the input file. [Leave blank for '...']: "
prompt2: "Please enter the name of the output file. [Leave blank for '...']: "
prompt3: "Press ENTER to continue. Any other key (+ enter) quits."
label1: "input filename:"
label2: "output filename:"
label3: "Number of emails:"
emptymsg: "I'm sorry, your input file is empty"
nonevalidmsg: "There are no valid email addresses in your input file."
goodbyemsg: Thanks for using this program. Have a great day!

SUBPROGRAMS:

***subprogram isValidEmailchar
Objective: test a character and see if it's a valid email character
DATA: [INPUT] c->character being checked [single character]
      [OUTPUT] result->whether c is valid or not [true/false]

***subprogram isDup
Objective: check if an email is equal to any of the emails in the list
DATA: [INPUT] subject->string being tested [string] [any string]
      [OUTPUT] result->whether subject is a duplicate or not [true/false]
      k->loop index [whole number] [any whole number > 0]

***subprogram lower
Objective: take each character in a string and put lowercase version of it in 'out'
DATA: [INPUT] given->the string to be made lowercase [string] [any string]
      [OUTPUT] out->the lowercase version of given [any string]
      h->loop index. Not using k because lower gets called from isDup. This way, value of k is preserved. [whole number] [any whole number > 0]


3. Instructions

***subprogram isValidEmailchar
1000 set result = false
1010 if c is between A-Z, a-z, 0-9, or is _, +, -, or ., set result = true
1020 return result to program that called
1030 return to program that called



***subprogram isDup
2000 set result = false
2010 set k = 0
2015 if k = size of 'email', skip to instruction 2060
2020 call subprogram lower on subject
2030 call subprogram lower on member of email at position k
2040 if 'out' from call to lower on subject == 'out' from call to lower on email_k, set result = true
2050 k = k + 1
2055 skip to instruction 2015
2060 return result to program that called
2070 return to program that called


***subprogram lower
3000 set out = given
3010 set h = 0
3015 if h = length of given, skip to instruction 3040
3020 character at position h in out = lowercase version of given_h
3030 h = h + 1
3035 skip to instruction 3015
3040 return out to program that called
3050 return to to program that called


***MAIN PROGRAM
10 output Introduction
20 output directions
30 dFile = "fileContainingEmails.txt"
40 enterKey = false
45 set empty = true
50 output prompt1, dFile
60 input iFile
70 if length of iFile = 0, then set enterKey = true
80 if enterKey = true, then iFile = dFile
90 if enterKey = true, skip to instruction 120
100 dFile = iFile
110 skip to instruction 130
120 dFile = "copyPasteMyEmails.txt"
130 output prompt2, dFile
140 input oFile
150 enterKey = false;
160 if length of oFile is 0, then enterKey = true
170 if enter key is true, then oFile = dFile
180 output label for the input file name, and iFile
190 output label for the output file name, and oFile
200 output prompt3
210 input keepGoing
220 if length of keepGoing > 0, skip to instruction 995
230 open iFile
240 if there are no problems with iFile, skip to instruction 270
250 send error message to OS
260 skip to instruction 999
270 if there are problems with iFile or iFile has ended, skip to instruction 570
280 set line = current line of iFile
290 if length of line = 0 skip to instruction 550
300 set i = 0
310 set empty = false
320 if i = length of line, skip to instruction 550
330 if character at position i in line not '@', skip to instruction 530
350 set s = (i - 1)
360 set e = (i + 1)
370 if s < 0 skip to instruction 410
375 call subprogram isValidEmailchar on character at position s in line
380 if result = false skip to instruction 410
390 set s = s - 1
400 skip to instruction 370
410 if e = the length of line, skip to instruction 470
412 call subprogram isValidEmailchar on character at position s in line
420 if result = false, skip to instruction 470
430 if character at position in line != '.' skip to instruction 460
440 set hasDot = true
450 dotPos = e
460 set e = e + 1
465 skip to instruction 410
470 set s = s + 1
475 if the following is FALSE, skip to instruction 510: (s < i) and (e > i) and (hasDot is true) and (dotPos > 1)
480 anEmail = the text between s and e
490 call isDup on anEmail
500 if result = true skip to instruction 530
510 output anEmail
520 add anEmail to list email
530 set i = i + 1
540 skip to instruction 320
550 move to next line
560 skip to instruction 270
570 if empty = false, skip to instruction 590
580 output emptymsg
590 if the size of list emails > 0, skip to instruction 620
600 output nonevalidmsg
610 skip to instruction 995
620 set m = 0
630 if m equals size of list email, skip to instruction 760
640 set n = m + 1
650 if n = size of list email, skip to instruction 740
660 call subprogram lower on email_m
670 call subprogram lower on email_n
680 if 'out' from lower on email_m <= 'out' from lower on email_n, skip to instruction 720
690 set temp = email_m
700 set email_m=email_n
710 set email_n = temp
720 set n = n + 1
730 skip to instruction 650
740 set m = m + 1
750 skip to instruction 630
760 open oFile
770 set i = 0
780 if i = size of list email, skip to instruction
790 output email_i
....(finish writing output loop basically)
... output label3 and size of list email
995 output goodbyemsg
999 END


4. Test Cases

(THERE ARE MORE TEST CASES NOW... I THINK)
*****Test Case#1: very simple, unproblematic usage

*What is being tested: simple- one line has two '@', another line has one '@'

*Input values if any:
	iFile = 'test.txt'
    CONTENTS:
    abc@123.com
  oFile = '\n'

*Expected result:
-Introduction
-Please enter the name of the input file. [Leave blank for 'fileContainingEmails.txt']:
-Please enter the name of the output file. [Leave blank for 'test.txt']:
-input filename: test.txt
-output filename: test.txt
-Press ENTER to continue. Any other key (+ enter) quits.
-abc@123.com
-number of emails: 1
-Thanks for using this program. Have a great day!

*Test:
10 Introduction
20 directions
30 dFile = "fileContainingEmails.txt"
40 enterKey = false
45 empty = true
50 prompt1, dFile
60 iFile = test.txt
100 dFile = iFile
110 skip to instruction 130
130 prompt2, dFile
140 oFile = '\n'
150 enterKey = false;
160 enterKey = true
170 oFile = dFile
180 label1, iFile
190 label2, oFile
200 output a prompt to press ENTER key to continue
210 keepGoing = '\n'
270 if there are problems with iFile or iFile has ended, skip to instruction 995
280 line = abc@123.com
300 i = 0
310 empty = false
330 skip to instruction 510
510 i= 0 + 1 = 1
520 skip to instruction 320
330 skip to instruction 510
510 i = 1 + 1 = 2
520 skip to instruction 320
330 skip to instruction 510
510 i = 2 + 1 = 3
520 skip to instruction 320
340 hasAt = 0 + 1 = 1
350 s = 3 - 1 = 2
360 e = 3 + 1 = 4
375 call isDup on line_2 ('c')
1000 result = false
1010 result = true
1020 return result to main program
390 s = 2 - 1 = 1
400 skip to instruction 370
375 call isDup on line_1 ('b')
1000 result = false
1010 result = true
1020 return result to main program
390 s = 1 - 1 = 0
400 skip to instruction 370
375 call isDup on line_0 ('a')
1000 result = false
1010 result = true
1020 return result to main program
390 s = 0 - 1 = -1
400 skip to instruction 370
370 skip to instruction 410
412 call isValidEmailchar on line_4 ('1')
1000 result = false
1010 result = true
1020 return result to main program
430 skip to instruction 460
460 e = 4 + 1 = 5
465 skip to instruction 410
412 call isValidEmailchar on line_5 ('2')
1000 result = false
1010 result = true
1020 return result to main program
430 skip to instruction 460
460 e = 5 + 1 = 6
465 skip to instruction 410
412 call isValidEmailchar on line_6 ('3')
1000 result = false
1010 result = true
1020 return result to main program
430 skip to instruction 460
460 e = 6 + 1 = 7
465 skip to instruction 410
412 call isValidEmailchar on line_7 ('.')
1000 result = false
1010 result = true
1020 return result to main program
440 hasDot = true
450 dotPos = 7
460 e = 7 + 1 = 8
465 skip to instruction 410
412 call isValidEmailchar on line_8 ('c')
1000 result = false
1010 result = true
1020 return result to main program
430 skip to instruction 460
460 e = 8 + 1 = 9
465 skip to instruction 410
412 call isValidEmailchar on line_9 ('o')
1000 result = false
1010 result = true
1020 return result to main program
430 skip to instruction 460
460 e = 9 + 1 = 10
465 skip to instruction 410
412 call isValidEmailchar on line_10 ('m')
1000 result = false
1010 result = true
1020 return result to main program
430 skip to instruction 460
460 e = 10 + 1 = 11
465 skip to instruction 410
410 skip to instruction 470
470 s = -1 + 1 = 0
480 anEmail = text between 0 and 11- abc@123.com
490 call isDup on abc@123.com
2000 result = false
2010 k = 0
2015 skip to instruction 2060
2060 return false to main program
510 abc@123.com
520 email_0 = abc@123.com
530 i = 3 + 1 = 4
540 skip to instruction 320
330 skip to instruction 530
510 i = 4 + 1 = 5
520 skip to instruction 320
330 skip to instruction 530
510 i = 5 + 1 = 6
520 skip to instruction 320
330 skip to instruction 530
510 i = 6 + 1 = 7
520 skip to instruction 320
330 skip to instruction 530
510 i = 7 + 1 = 8
520 skip to instruction 320
330 skip to instruction 530
510 i = 8 + 1 = 9
520 skip to instruction 320
330 skip to instruction 530
510 i = 9 + 1 = 10
520 skip to instruction 320
330 skip to instruction 530
510 i = 10 + 1 = 11
320 skip to instruction 550
560 skip to instruction 270
270 skip to instruction 570
570 skip to instruction 590
590 skip to instruction 620
620 label3, 1
995 goodbyemsg
999 END

*****Test Case#2: both defaults

*What is being tested: user only enters ENTER key, no custom values (then quits program execution)

*Input values if any:
	iFile = '\n'
  oFile = '\n'

*Expected result:
-Introduction
-Please enter the name of the input file. [Leave blank for 'fileContainingEmails.txt']:
-Please enter the name of the output file. [Leave blank for 'copyPasteMyEmails.txt']:
-input filename: fileContainingEmails.txt
-output filename: copyPasteMyEmails.txt
-Press ENTER to continue. Any other key (+ enter) quits.
-Thanks for using this program. Have a great day!

*****Test Case#3: custom input filename

*What is being tested: user wants different input file from default, and uses the same file for output

*Input values if any:
	iFile = 'x.txt'
    CONTENTS:
    abc@123.com
  oFile = '\n'

*Expected result:
-Introduction
-Please enter the name of the input file. [Leave blank for 'fileContainingEmails.txt']:
-Please enter the name of the output file. [Leave blank for 'x.txt']:
-input filename: x.txt
-output filename: x.txt
-Press ENTER to continue.
-abc@123.com
-number of emails: 1
-Thanks for using this program. Have a great day!

*****Test Case#4: custom output filename

*What is being tested: user wants different output file from default, and uses the same file for output

*Input values if any:
	iFile = '\n'
    CONTENTS [fileContainingEmails.txt] :
    abc@123.com
  oFile = 'y.txt'

*Expected result:
-Introduction
-Please enter the name of the input file. [Leave blank for 'fileContainingEmails.txt']:
-Please enter the name of the output file. [Leave blank for 'copyPasteMyEmails.txt']:
-input filename: fileContainingEmails.txt
-output filename: y.txt
-Press ENTER to continue.
-abc@123.com
-number of emails: 1
-Thanks for using this program. Have a great day!

*****Test Case#5: both custom filenames

*What is being tested: user wants different input AND out file from default

*Input values if any:
	iFile = 'x.txt'
    CONTENTS:
    abc@123.com
  oFile = 'y.txt'

*Expected result:
-Introduction
-Please enter the name of the input file. [Leave blank for 'fileContainingEmails.txt']:
-Please enter the name of the output file. [Leave blank for 'x.txt']:
-input filename: x.txt
-output filename: y.txt
-Press ENTER to continue.
-abc@123.com
-number of emails: 1
-Thanks for using this program. Have a great day!

*****Test Case#6: user wants to quit (change filenames)

*What is being tested: user makes a mistake with output filename

*Input values if any:
	iFile = 'test.txt'
    CONTENTS:
    @@
    \n
    @
  oFile = reddit.com

*Expected result:
-Introduction
-Please enter the name of the input file. [Leave blank for 'fileContainingEmails.txt']:
-Please enter the name of the output file. [Leave blank for 'test.txt']:
-input filename: test.txt
-output filename: reddit.com
-Press ENTER to continue. Any other key (+ enter) quits.
-Thanks for using this program. Have a great day!

*****Test Case#7: user makes filename mistake and doesn't fix it

*What is being tested: user makes a mistake with input filename

*Input values if any:
	iFile = reddit.com
  oFile = '\n'

*Expected result:
-Introduction
-Please enter the name of the input file. [Leave blank for 'fileContainingEmails.txt']:
-Please enter the name of the output file. [Leave blank for 'reddit.com']:
-input filename: reddit.com
-output filename: reddit.com
-Press ENTER to continue. Any other key (+ enter) quits.
-error message sent to OS
-program failure

*****Test Case#8: file contains no emails

*What is being tested: input file just has non-email text

*Input values if any:
	iFile = 'test1.txt'
    CONTENTS:
    at at
    \n
    at
  oFile = '\n'

*Expected result:
-Introduction
-Please enter the name of the input file. [Leave blank for 'fileContainingEmails.txt']:
-Please enter the name of the output file. [Leave blank for 'test1.txt']:
-input filename: test1.txt
-output filename: test1.txt
-Press ENTER to continue. Any other key (+ enter) quits.
-Your input file contains no emails.
-Thanks for using this program. Have a great day!

*****Test Case #9: file is empty

*What is being tested: nothing in input file- no characters, only end of file marker (if applicable)

*Input values if any:
	iFile = 'test2.txt'
    CONTENTS:

  oFile = '\n'

*Expected result:
-Introduction
-Please enter the name of the input file. [Leave blank for 'fileContainingEmails.txt']:
-Please enter the name of the output file. [Leave blank for 'test2.txt']:
-input filename: test2.txt
-output filename: test2.txt
-Press ENTER to continue. Any other key (+ enter) quits.
-I'm sorry, your input file is empty
-Thanks for using this program. Have a great day!

******Test Case #10: input file has multiple duplicate emails

*What is being tested: ability to distinguish exact duplicates

*Input values if any:
	iFile = 'test3.txt'
    CONTENTS:
	abc@123.com
	abc@123.com
  oFile = '\n'

*Expected result:
-Introduction
-Please enter the name of the input file. [Leave blank for 'fileContainingEmails.txt']:
-Please enter the name of the output file. [Leave blank for 'test3.txt']:
-input filename: test3.txt
-output filename: test3.txt
-Press ENTER to continue. Any other key (+ enter) quits.
-abc@123.com
-number of emails: 1
-Thanks for using this program. Have a great day!

******Test Case #11: input file has the same email more than once, but cased differently

*What is being tested: ability to distinguish cases

*Input values if any:
	iFile = 'test4.txt'
    CONTENTS:
	abc@123.com
	ABC@123.com
	abc@123.com
  oFile = '\n'

*Expected result:
-Introduction
-Please enter the name of the input file. [Leave blank for 'fileContainingEmails.txt']:
-Please enter the name of the output file. [Leave blank for 'test4.txt']:
-input filename: test4.txt
-output filename: test4.txt
-Press ENTER to continue. Any other key (+ enter) quits.
-abc@123.com
-number of emails: 1
-Thanks for using this program. Have a great day!