Need help with strings in structures

[valium123]

I am using irvine32.inc and want to display a string using the writeString procedure.
Suppose there is a structure defined as:

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Person struct
     name byte 10 dup(?)
Person ends
personArray Person 3 dup(?)


I have tried this:
mov ecx, 3
mov esi, type Person
L1:
     mov edx, offset personArray[esi].name
      mov writestring
      add esi, type Person
loop L1

But it doesnt work. Please help.

[dedndave]

you're really close 

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Person struct
  name byte 10 dup(?)
Person ends

    .DATA?

personArray Person 3 dup(<>)

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        mov     ecx, 3
        mov     esi, offset personArray
L1:
        mov     edx, [esi].Person.name
        call    WriteString
        add     esi, sizeof Person
        loop    L1

[valium123]

Thanks for replying. I am using visual studio right now and this error comes up when try your solution:
1>main.asm(103): error A2022: instruction operands must be the same size

[jj2007]

Thanks for replying. I am using visual studio right now and this error comes up when try your solution:
1>main.asm(103): error A2022: instruction operands must be the same size

Please send the IP and password of your computer, so that those who want to help you can launch a Remote Desktop Connection that allows them to see what you have coded in line 103.

[valium123]

Dude I mentioned above that when I try the solution posted, the error appears. Its obvious that the line containing "mov edx" is causing problems.

[jj2007]

Dude it's not obvious but I'll be kind because you sound desperate:

Person struct
  xname byte 10 dup(?)   ; "name" is a bad choice
Person ends
...
        lea edx, [esi].Person.xname   ; unless you want the first 4 bytes only, of course

[valium123]

thanks but the problem is we have not studied lea yet. I need to use something like

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mov edx, offset msg
call writestring


:(

And the code is much longer than the example I wrote above. Will you have look at my code if I send it to you?

[dedndave]

my mistake - please change this line

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L1:
        lea     edx, [esi].Person.name

LEA stands for "load effective address"
it calculates the address of [esi].Person.name and places it in edx

because the member "name" is at the beginning of the structure,
you could just use

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        mov     edx,esi
but, that's not a good solution if Person is updated

[dedndave]

another solution - not as pretty, but workable...

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        mov     ecx, 3
        mov     esi, offset personArray.Person.name
L1:
        mov     edx, esi
        call    WriteString
        add     esi, sizeof Person
        loop    L1

[dedndave]

i actually tried this - the member name "name" is not good - leads to errors

this code assembles OK...

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;###############################################################################################

        INCLUDE    \Masm32\Include\Masm32rt.inc

;###############################################################################################

Person STRUCT
  pname db 10 dup(?)
Person ENDS

;###############################################################################################

        .DATA?

personArray Person 3 dup(<>)

;###############################################################################################

        .CODE

;***********************************************************************************************

main    PROC

        mov     esi,offset personArray.Person.pname

        inkey
        INVOKE  ExitProcess,0

main    ENDP

;###############################################################################################

        END     main

[valium123]

There is another problem

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input_details PROC uses ecx esi edi
           mov ecx, 6
           mov esi, type flightInfo
           L1:
        inc edi
mov edx, offset msg1
call writestring
mov edx, offset flights
add edx, esi
mov ecx, SIZEOF (flightInfo ptr [edx]).F_airline
call readstring

mov edx, offset msg2
call writestring
mov edx, offset flights
add edx, esi
mov ecx, SIZEOF (flightInfo ptr [edx]).F_from
call readstring

mov edx, offset msg3
call writestring
mov edx, offset flights
add edx, esi
mov ecx, SIZEOF (flightInfo ptr [edx]).F_to
call readstring
                add esi, type flightInfo
            LOOP L1
                ret
input_details ENDP           


Is this correct coz I feel that it is overwriting previously entered strings.

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flightInfo STRUCT
F_airline byte 20 dup(0)
F_from byte 10 dup(?)
F_to byte 10 dup(?)
F_departure_time byte 7 dup(?)
F_arrival_time byte 7 dup(?)
F_Duration dword ?
F_seats dword ?
F_ticket dword ?
F_flight_ID dword ?
flightInfo ENDS





[dedndave]

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flightInfo STRUCT
F_airline byte 20 dup(0)

while it is allowed to use initialized variables inside structure definitions, we rarely do so
it makes a very different animal than an uninitialized structure
mainly, any use of flightInfo must be in the .DATA section - not the .DATA? section

i would probably use

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F_airline byte 20 dup(?)

the uninitialized data section is set to all 0's at program startup

[dedndave]

i see that Kip's ReadString funtion uses ReadConsole
i seem to recall that ReadConsole always wants a 256-character buffer, regardless of the documentation

http://masm32.com/board/index.php?topic=3572.msg37552#msg37552

if that's the case, i would use a common 256-character buffer for all user input
then, move the desired limited string length into the destination buffer each time

[dedndave]

you might do this....
write a PROC that handles keyboard input - pass the address and size of the buffer
use a LOCAL buffer that allows at least 256 characters
if the user input exceeds the buffer size parameter, display a "string too long" message and try again

[qWord]

According to the MASM 6.1 reference manual the NAME directive is ignored =>it is perfectly OK to remove that keyword at the begin of your program:

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option nokeyword:<name>