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Frequency Table

Started by, August 03, 2012, 05:03:05 AM

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I have been working on the below code for about a week now, and have been working with my professor, but still to no avail I haven't gotten it to work fully. This is a course required for my major, while I have no actual interest in programming, I am almost done with the class and this is my final project. I have a very naive understanding of the class but have successfully fumbled my way until here. I have posted my code below. It is compiling, however when I start it without debugging it times out and then says press and key to continue.... it is not giving me back any of the required data and I have no idea where to go from here, and the program is due at midnight :(

target BYTE " AAEBDCFBBC" , 0
freqTable DWORD 256 DUP( 0)


main PROC
       call Clrscr
       call Get_frequencies
       call DisplayTable

main ENDP

Get_frequencies PROC,
pString:PTR BYTE,; points to string
pTable:PTR DWORD; points to frequencey table
; Constructs a character frequency table. Each array position
; is indexed by its corresponding ASCII code.
; Returns: Each entry in the table contains a count of how
; many times that character occurred in the string.

mov esi,pString
mov edi,pTable
cld; clear Direction flag (forward)

L1:mov eax,0; clear upper bits of EAX
lodsb; AL = [ESI], inc ESI
cmp al,0; end of string?
je Exit_proc; yes: exit
shl eax,2; multiply by 4
inc DWORD PTR[edi+eax]; add to table entry
jmp L1; repeat loop

Get_frequencies ENDP

DisplayTable PROC
; Display the non-empty entries of the frequency table.
; This procedure was not required, but it makes it easier
; to demonstrate that Get_frequencies works.
colonStr BYTE ": ",0
call Crlf
mov ecx,LENGTHOF freqTable; entries to show
mov esi,OFFSET freqTable
mov ebx,0; index counter

L1: mov eax,[esi]; get frequency count
cmp eax,0; count = 0?
jna L2; if so, skip to next entry

mov eax, ebx; display the index
call WriteChar
mov edx, OFFSET colonStr; display ": "
call WriteString
mov eax,[esi]; show frequency count
call WriteDec
call Crlf

L2:add esi, TYPE freqTable; point to next table entry
inc ebx; increment index
loop L1

call Crlf
DisplayTable ENDP

END main

Please help!


Quote from: ncmoore91 on August 03, 2012, 05:03:05 AM
while I have no actual interest in programming, ... the program is due at midnight :(

Well, if you really worked a week on it, then you merit a little help:

mov esi, offset target      ;pString
mov edi, offset freqTable   ;pTable

It will still crash a little bit, but your teacher will accept it :biggrin:

: 1
A: 2
B: 3
C: 2
D: 1
E: 1
F: 1


when i was in school, i had no interest in Chemistry - or History - or a few others

i wish, now, that i had paid more attention   :t