help with file i/o

[niazdokrat]

hey i am trying to write a program that saves logs and i have basically 3 columns session time,total time and comments in that order

what i want to do is read in the total time on the last line, and store it in 3 variables hr, min, sec then add the current session time to get teh new total time .

i was trying to use StreamReader and the compiler is visual c++ 2003

a sample of the first line in the log file is below:

00 : 00 : 04 --- 00 : 00 : 04 --- Comments...

any help will be much appreciated thanks

oh and sorry if this is in the wrong forum im new here lol

[Shashi Sadasivan]

hi,

this would most probably be shifted to the C++ forums.

But anyhows...
Is your issue that you do not know how to start coding your pseudo code?
or are you facing issues within the code execution?

cheers

[niazdokrat]

well i guess i am having problems with code... this is my first real windows forms project... anyways the problem is that i need something that will work like fscanf in C so that i can read in the integers or even the numbers as a string up to the whitespace which i can then convert to an int.

am i making myself clear?

i was using the streamreader class but Read() only reads a single char and ReadLine() isnt applicable here... ReadBlock() seems to be the better choice but the complicated data types makes it too confusing and hard to implement.

i was even thinkin abt reading each number as a letter and convert to in then multiply by 10 and add the number after it so for e.g 48 =(4x10)+8 but that seems like too long a roundabout way to do it.

[Shashi Sadasivan]

have you been able to read the file?

C++ should have an equivalent of what .Net has "Split"
So read each line in your file, and then once you have the last line.. use the split on that line, splitting on "---" so that you can get all 3 fields in seperate strings.

cheers

[niazdokrat]

ok thanks for the help but i am still having some probs

String* tempLine;
String *splitLines[] = NULL;
//String *time[] =NULL;

char splitter[] = {" --- "};
//Char splitter2[] = " : ";


splitLines = tempLine->Split(splitter);

the compiler is telling me that it cannot convert from char[6] to __wchar_gc
even if i put the delimiter in directly

[niazdokrat]

no help from anyone???

[Plater]

Not many people use c++ for .NET applications. So most of us are probably scratching our head. VB.NET and C# differ mostly by simple syntax convention.
C++ with .NET seems to be waaay different.

I have no idea what a __wchar_gc is.

But if you manage to get a string[] of the values, There should be like Int.Parse() and Double.Parse() and various other datatypes all have the .Parse() function which will take a string and attempt to make a datatype from it.

i.e. int myint =int.Parse("123");//makes myint=123

[niazdokrat]

hmmm thanks for the reply...yeh i realise ppl mostly use c# and VB the prob is that i dont know either lol... anyways i'll try your advice and see if it works.

[niazdokrat]

ok that didnt work.... i tried rewriting the function and this is what i have (well the part that deals with the reading from file....

FileStream *fst = new FileStream(sfd->FileName,FileMode::OpenOrCreate);
             FileInfo *fptr = new FileInfo(sfd->FileName);
             BinaryReader *freader = new BinaryReader(fst);
             StreamWriter *fwriter = new StreamWriter(fst);
             int oldHr ,oldMin, oldSec, lineCount=0;
 
             if (File::Exists(sfd->FileName)){
                 while (freader->ReadString() != NULL){
                    lineCount++;
                 }
 
                freader->BaseStream->Position= 0;
                for (int i=0; i< (lineCount -1);i++)
                    freader->ReadString();
                for (int j=0; j<17; j++)
                    freader->Read();
 
                oldHr = freader->ReadInt32();
                freader->ReadChars(3);
                oldMin = freader->ReadInt32();
                freader ->ReadChars(3);
                oldSec = freader->ReadInt32();
 
 
                    oldSec += sec;
                    if (oldSec >= 60){
                        oldMin++;
                        oldSec -=60;
                    }
                    oldMin += min;
                    if (oldMin >=60){
                        oldHr++;
                        oldMin -=60;
                    }
                    oldHr += hr;
 
                    fwriter = fptr->AppendText();  // if it exists append to file
             }
 
 

[Shashi Sadasivan]

is it giving any errors?
I would presume that readInt32 would be causing your problem.
As the file is a text file, and you are reading binary data from it for int32 ie(4bytes = 4 characters)
I think you should read it as characters and then convert it to integers.

cheers

[niazdokrat]

it compiles fine... but now that i redid it it is giving the error 'unable to read beyond end of stream' when i try to save the file (when it reads the file)

i think im getting that error because now with binary stream im not sure how to get to the last line

before i was using StreamReader but i couldnt get the data i needed from the line.

[Shashi Sadasivan]

Compilation wouldnt be a problem.
it will be at runtime because you are trying to read more data than what the file actually has.
lets take this example
00 : 00 : 00
this takes 12 bytes
if we take the concept of reading int32 then 3 chars then int32 then 3 chars and then int32,
then that means u are reading 4 + 3 + 4 + 3 + 4 = 18bytes.
no wonder it runs out of the file.

So read it as chars, and convert the chars to int.

cheers