Easy Problem?: How to open/read a datafile

This is a discussion on Easy Problem?: How to open/read a datafile within the C Programming forums, part of the General Programming Boards category; Hi, I have this program - im pretty sure its coded correctly, and i have a datafile - basically its ...

  1. #1
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    Easy Problem?: How to open/read a datafile

    Hi, I have this program - im pretty sure its coded correctly, and i have a datafile - basically its just a few lines of numbers. Anyways im not sure about the procedure on how to open/read datafiles with the example below.

    Basically my program is about a mayors race with 4 candidates. I allready programed everything to count all the votes, percentage of votes, if a candidate has 50% of the vote he wins and it declares he/she the winner, if nobody gets 50% then it declares a runoff. Anyways im just having a problem opening and reading the datafile with all the vote figures. All the work i put into the code is useless if i cant read the datafile inputs!

    For example: datafile.txt (4 candidates = 4 columns of votes)
    192 48 206 37
    147 90 312 21
    186 12 121 38
    114 21 408 39
    267 13 382 29

    I use olympus to compile and run my program.
    gcc mayorrace.c (compiles the program - compiles fine)
    a.out -datafile.txt (runs the compiled program also points to the datafile - basically it just sits there and does nothing - i push escape and then it outputs alot of 0's instead of the actual datafile votes)

    Code:
    Precinct        Candidate A     Candidate B     Candidate C     Candidate D
    1               0               0               0               134396          
    2               0               0               0               -12687724               
    3               0               0               0               0               
    4               0               0               -4260984                0               
    5               0               0               224592          0               
    Total           0               0               -4036392                -12553328               
    Percent         0               0               24              76
    What do i need to do? Thanks for your time Any tips would be greatly appreciated.

    The last program i had that used a datafile i used this line:
    FILE *fpr = fopen("datafile.txt", "r");
    but thats not working very well this time, either that or i dont know where to put it...
    Last edited by zipfur; 11-15-2002 at 02:04 PM.

  2. #2
    ATH0 quzah's Avatar
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    Text files are always opened the same. You either open for reading or writing. It's always done the same. It's up to you how you read that data however.

    Take a gander at fopen, fgets, fgetc, and fclose to get you started.

    Quzah.
    Hope is the first step on the road to disappointment.

  3. #3
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    Thanks!
    a.out < datafile.txt makes the program work like a charm!

  4. #4
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    Zip, I'm in that class as well. I'm rather lost on how you got the array to read from a datafile...

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