Thread: Read numbers from a text file

  1. 08-13-2011 #1
    fred_maes
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    Unhappy Read numbers from a text file

    Hello, I'm a big fan of this website and it has helped me a lot in the past years, but unfortunately this time I can't find an answer to my problem here. I hope someone can help me out!

    I'm trying to read numbers (integers) from a text file consisting of random text and numbers. The numbers in the text are marked by "quotes", but I just can't figure out how I have to extract them. It would also be sufficient if I knew how to compare these numbers with an array (integers) I've already created (in general I just need to know which numbers from the text can also be find in the array).

    I've tried extracting the numbers, but I can only get characters (f.e. if I extract the number '1', I get the ASCII value '49'). I've also tried searching the text (loading text in a buffer) and comparing each character with the values from the array, but nothing...
  2. 08-13-2011 #2
    Prelude
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    If the numbers are surrounded by quotes, finding them should be easy. Then you can collect them into a string and use strtol() to convert the number to an integer.
    My best code is written with the delete key.
  3. 08-13-2011 #3
    AndrewHunter
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    Possible options(depending on file format since I am not sure):

    1. fscanf().
    2. Using an fgets/sscanf pair.
    3. Working with the solution you already have in place, you can convert a string to an integer with atoi
    4. If you just have a char, say '1' then if you do this: number = charNum - '0'. This will give you the integer equivalent of your character number.
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  4. 08-13-2011 #4
    CommonTater
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    If you have a text file like this....
    Code:
    fred "1003" is a very crazy "10032" caveman
    ... and the quotes rule always holds you should be able to use fscanf("\"%d\"",&myint); to extract the numbers.

    Look up fscanf() in your C library documentation (which should be supplied with your compiler).
  5. 08-13-2011 #5
    fred_maes
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    Thanks for quick reply!

    I'll look into the fscanf solution since the rule does indeed always hold.
  6. 08-13-2011 #6
    fred_maes
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    Was indeed already very closed. Found the solution about one hour ago. Thanks for support! Wouldn't have found it without the tips!
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