C++ Reading in text file

[SargeRX8]

I have a text file with content like the following.

[0,7,19,3,1092][1,5,16,4,1064][2,15,14,3,1740][3,4,5,3,1048][4,7,11,2,1278]

How do i go about reading in each block? For example we have [0,7,19,3,1092]

Lets say i declare 5 variables, x1 x2 x3 x4 x5.

I want 0 to go to x1, 7 to x2, 19 to x3, 3 to x4 and 1092 to x5.

I want to then complete a set of tasks on these variables. Once that task is complete i will then read in the next block [1,5,16,4,1064] over these variables.

Any ideas?

[Khaless]

using file functions, ifstream etc etc etc.

and then create a simple parser that relies on state.

if [ then we create a new collection and append it to our total collections,
if its a number, add it to the current collection etc etc.

[SargeRX8]

So like

ill read in 1 char and if the first char is the opening [ i will have a second statement within that loop or what ever to read in x(the value) with the , as a delimiter until it reads the ] then break the loop and repeat until EOF

[Jayso]

Or you can use functions like String.Split()

Pressing F1 is the best way to find out about how it works (Assuming you're using Visual Studio )

[nuk3]

Originally Posted by Jayso

Or you can use functions like String.Split()

Pressing F1 is the best way to find out about how it works (Assuming you're using Visual Studio )

I know nothing about c++, but I'll just make a generalised probably unfounded observational pointless comment:

streaming the file in and parsing it on the fly would be a lot more efficient than loading the entire contents of the file into memory (could be 100's mbs) and performing string operations on it, considering each block of data in the file is only temporary/stateless and has no bearing on anything else, so there's no reason to have it all available at any one time.

but anyway, khaless = 3rd year HIGH honour roll IT uni student, so yeah, he's a smart cookie, good kid, tries hard

[Khaless]

Originally Posted by nuk3

I know nothing about c++, but I'll just make a generalised probably unfounded observational pointless comment:

streaming the file in and parsing it on the fly would be a lot more efficient than loading the entire contents of the file into memory (could be 100's mbs) and performing string operations on it, considering each block of data in the file is only temporary/stateless and has no bearing on anything else, so there's no reason to have it all available at any one time.

but anyway, khaless = 3rd year HIGH honour roll IT uni student, so yeah, he's a smart cookie, good kid, tries hard

How did you know that? I hope it was Tim, and you were not stalking me... I'm Honours Now (4th year)

Yes, the reason I did not say any string functions is, what if the data file is very large, and with no new lines etc to buffered read on?

[nuk3]

Originally Posted by Khaless

How did you know that? I hope it was Tim, and you were not stalking me... I'm Honours Now (4th year)

Yes, the reason I did not say any string functions is, what if the data file is very large, and with no new lines etc to buffered read on?

haha yeah, tim told me, but if it makes you feel any better I've been tapping into your interwebs and stoling your megahurtz.

[Jayso]

Woops I got this confused with C#.... Think it was when I read the "C# HALP" link which is the previous thread... heh

String.Split may still work... I don't know crap about C++

[SargeRX8]

OK, my solution is this.

This Tokenizer function was found on the net.

void Tokenize(const string& str,
                      vector<string>& tokens,
                      const string& delimiters = " ")
{
    string::size_type lastPos = str.find_first_not_of(delimiters, 0);
    string::size_type pos     = str.find_first_of(delimiters, lastPos);

    while (string::npos != pos || string::npos != lastPos)
    {
        tokens.push_back(str.substr(lastPos, pos - lastPos));
        lastPos = str.find_first_not_of(delimiters, pos);
        pos = str.find_first_of(delimiters, lastPos);
    }
}

I used this along with this piece of code

do{
        getline(inputFile,str,'[');
        Tokenize(str, tokens,",");

    }while(!inputFile.eof());

The '[' skips that character in when reading each block. The tokenizer reads in each value up to the ,.

I then incorporated this piece of code to store the data from the text file into an array of objects(i was going to use an vector of objects but the hell with that).

for (unsigned int i = 0; i < tokens.size() ;i=i+5)
    {

        temp=tokens[i+4];
        temp=temp.substr(0, temp.length() - 1);

        objOrder[x].orderId = atoi(tokens[i].c_str());
        objOrder[x].PCid = atoi(tokens[i+1].c_str());
        objOrder[x].quantity = atoi(tokens[i+2].c_str());
        objOrder[x].dueDate = atoi(tokens[i+3].c_str());
        objOrder[x].profit = atoi(temp.c_str());
        /**** Reference Block ****/
        /* OrderStatus 0 = First */
        /* OrderStatus 1 = Delay */
        /* OrderStatus 2 = Cancel*/

        objOrder[x].totalProfit = objOrder[x].profit * objOrder[x].quantity - (objProduct.pccycle(objOrder[x].PCid)*100*objOrder[x].quantity);
        if(objOrder[x].totalProfit<=0){
            objOrder[x].orderStatus = 1;
        }else{
        objOrder[x].orderStatus = 0;
        }
        x++;
    }

I cheated abit in getting rid of the ] at the end of the block. What i done was read in the value after the comma, say for example the end of the block is ..,9]. What i done was read in the 9] then use a string function(in bold) to remove -1 from the end of the string...seems to work just fine

Thanks for the help.

[shirasE_]

tl;dr

split function.

[SargeRX8]

Originally Posted by shirasE_

tl;dr

split function.

Theres no standard split function in C++, but the code i used sorts that issue out.

[chemicalNova]

Just thought I would add.. that there is in fact strtok() which does pretty much what that internet version does in STL.

chem