QBasic question

[Ben321]

Ok, so I decided to go back and use some QBasic just for the sake of some retro programing fun.

I know in VB6 if you want to check for a file you can use the Dir or Dir$ command. For example:

dim FileName as string
FileName = "MyFile.txt"
if dir(FileName) <> "" then
print "File exists."
else
print "File is missing."
end if

But QBasic doesn't have Dir or Dir$. So what is the equivalent QBasic command?

[si_the_geek]

Thread moved from 'VB6 and Earlier' forum (which is only meant for VB) to the 'Other BASIC' forum

[Ben321]

Why does it seem nobody knows the answer to this?

[whatsup]

i don't if there is
a quick search in google, i found this : http://social.msdn.microsoft.com/For...8-fdb33e324ac0

BTW: if you are after good basic interpreter, take a look at this: wxBasic.net
can run on several platforms

[Ben321]

i don't if there is
a quick search in google, i found this : http://social.msdn.microsoft.com/For...8-fdb33e324ac0

BTW: if you are after good basic interpreter, take a look at this: wxBasic.net
can run on several platforms

Thanks but I'm not looking to generate a txt file directory listing. I'm looking for the QBasic equivalent of the VB6 command "Dir" or "Dir$". The Dir command in VB6 is a function which when a file name is put into it, its return value is a string containing nothing if the file isn't there, and the name of the file if it is there. It returns it meaning it can be DIRECTLY put into a variable so I can have like:

dim TestStr as string
TestStr = dir("myfile.dat")

What you have showed me does NOT return a value to QBasic, but rather simply executes the dos command "Dir". I already tried this:

dim TestStr as string
TestStr = shell dir("myfile.dat")

But that didn't work.

I'm going on the assumption that Dir and Dir$ in VB6 are direct ports of a QBasic command with a similar name (such as DirFind, Find, FileFind, or something like that). But I can't find any QBasic documentation on the internet that names the QBasic equivalent of VB6's Dir and Dir$. But I'm sure such a command exists. Please help me.

[dilettante]

VB6 isn't actually descended from QBasic.

QBasic was a fork from an early version of QuickBasic (4.5), meant as a replacement for GW-Basic. It pretty much stagnated where it was. VB took another path, going through Basic Professional Development System (PDS).

VBDOS 1.0 was actually a later version of PDS, and came out just after VB 1.0 for Windows. VBDOS does have Dir$.

The DIR$ functions was introduced in Microsoft Basic PDS for MS-DOS and MS OS/2, version 7.0.

Examples of Loading MS-DOS Directory Listing into an Array

[Ben321]

VB6 isn't actually descended from QBasic.

QBasic was a fork from an early version of QuickBasic (4.5), meant as a replacement for GW-Basic. It pretty much stagnated where it was. VB took another path, going through Basic Professional Development System (PDS).

VBDOS 1.0 was actually a later version of PDS, and came out just after VB 1.0 for Windows. VBDOS does have Dir$.


Examples of Loading MS-DOS Directory Listing into an Array

But does QBasic have an EQUIVALENT command for Dir$?

And what is the difference between QBasic and QuickBasic? I thought they were the same, with the "Q" in QBasic being short for the word "Quick".

[dilettante]

No there is no Dir$() or equivalent in QBasic.

QBasic was a stripped down version of an old QuickBasic without a compiler and linker. You are left with the IDE and interpreter, so programs cannot be compiled and thus run much more slowly than compiled QuickBasic programs.

QuickBasic had no Dir$() either.

[abhijit]

But does QBasic have an EQUIVALENT command for Dir$?

And what is the difference between QBasic and QuickBasic? I thought they were the same, with the "Q" in QBasic being short for the word "Quick".

You might be interested in this link.

[Peter Swinkels]

Let's see,

If you want to do the following things in Qbasic:

-Check whether a file exists:

OPEN path FOR INPUT AS #n: CLOSE #n

If the specified file doesn't exist this will cause an error upon execution, which you probably want to cath using the ON ERROR statement.


-Display a list of files in a directory:

FILES "pattern"

Though limited in what it can do, the FILES statement might still be useful to you.


-Write the contents of a directory to a file, which can then be read by your Qbasic program:

SHELL "DIR path /B>file"

Hope this helps.