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Is it possible to arange lines in a file alphabetically?

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Is it possible to arange lines in a file alphabetically?

Nov 20th, 2006

OK, so the part of my course about files is over, but now I am wondering: if you have a file with, say, a bunch of names (each in its own line), is it possible to use "C" to make a new file with the names aranged alphabetically? For example, if the original file is:

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c Syntax (Toggle Plain Text)

Mike
Carl
John
Babe
Ferrari

the new one should be

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c Syntax (Toggle Plain Text)

Babe
Carl
Ferrari
John
Mike

If it can be done...well, explain how.

P.S. I'm asking because I want to arange my list of music albums, because right now, the names are held in a completely sporadic manner in a Word document.:cheesy:

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Re: Is it possible to arange lines in a file alphabetically?

Nov 20th, 2006

Read all the lines into a container in your program. Sort the container. Then write the contents of the container back to your file, overwriting the previous unsorted contents of the file. What container you use is up to you based on your knowledge and experience. What sorting algorhythm you use is up to you, too, but choices include bubble sort, quick sort, insertion sort, etc.

A Word file probably has a lot of extraneuous gunk in it to make it pretty when you open the file in Word. If you can save the contents in a plain text file, like you would get with Note Pad, that might be easier to read from, unless you know the specific set up of the Word file. Of course, if you have no trouble reading in the Word file, then you don't have to worry about this paragraph.

Last edited by Lerner; Nov 20th, 2006 at 12:20 pm.

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Re: Is it possible to arange lines in a file alphabetically?

Nov 20th, 2006

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Originally Posted by Lerner

Read all the lines into a container in your program.

This might sound stupid...but what is a container? Either it's an English word for something I'm familiar with (English isn't my first language) or I simply don't know what it is.

And please name some containers.

Word formatting isn't a problem.

Last edited by Sin-da-cat; Nov 20th, 2006 at 12:32 pm.

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Re: Is it possible to arange lines in a file alphabetically?

Nov 20th, 2006

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Originally Posted by Sin-da-cat

P.S. I'm asking because I want to arange my list of music albums, because right now, the names are held in a completely sporadic manner in a Word document.:cheesy:

Copy and paste the contents of the word file in a clean text file to avoid unnecessary hassles. I dont think there would be a requirement of your course to read specificallly from a *word file* .

Word File is not a text editor but used to present text and such tools are not used for storing data. Data files of user either have a header format which the user has designated (like a game's save file) and he knows or they are just pure text with custom extension (names.sdc) .

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This might sound stupid...but what is a container? Either it's an English word for something I'm familiar with (English isn't my first language) or I simply don't know what it is.
And please name some containers.

Simply put a container is something which is used to store loads of data or records and which can be accssed in O (1) time if the index of that element is know.

THe basic containers are well -- arrays

in C and Vectors in C++.
If you using arrays you can use the inbuilt qsort( ) method to sort the array and if you usign vectors you can use the inbuilt sort( ) algorithm.

Last edited by ~s.o.s~; Nov 20th, 2006 at 12:33 pm.

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Re: Is it possible to arange lines in a file alphabetically?

Nov 20th, 2006

>>but what is a container?

an array, std::vector, std::list, etc.

Don't PM me with questions -- you might get a nasty PM in response. If you have a question then post it in one of the forums.

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Re: Is it possible to arange lines in a file alphabetically?

Nov 20th, 2006

<snip>, it was a stupid question.:rolleyes:

I know about Word not being a pure text editor, I was gonna paste it into a notepad file.

Thanks.

Last edited by Ancient Dragon; Nov 20th, 2006 at 3:33 pm.

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Re: Is it possible to arange lines in a file alphabetically?

Nov 20th, 2006

Here comes another stupid question: how do you use qsort?

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Re: Is it possible to arange lines in a file alphabetically?

Nov 20th, 2006

For a solved eg. see here.

For documentation look here.

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Re: Is it possible to arange lines in a file alphabetically?

Nov 20th, 2006

 Help with Code Tags 
 c Syntax (Toggle Plain Text) 
main(){
FILE *a,*b;
char s[100];
int i=0,k;
char starr[50][101];                      /*50 - the number or strings I wanna put in the array*/
a=fopen("C:\\C_fajlovi\\non_sorted.txt","r");
b=fopen("C:\\C_fajlovi\\sorted.txt","w");    /*made a new file, want to keep the previous one too*/
while(fscanf(a,"%s",&s)!=EOF){
 starr[i]=s;
    i++;
    }
 
...
main(){
FILE *a,*b;
char s[100];
int i=0,k;
char starr[50][101];                      /*50 - the number or strings I wanna put in the array*/
a=fopen("C:\\C_fajlovi\\non_sorted.txt","r");
b=fopen("C:\\C_fajlovi\\sorted.txt","w");    /*made a new file, want to keep the previous one too*/
while(fscanf(a,"%s",&s)!=EOF){
 starr[i]=s;
    i++;
    }
 
...

Why do I get 'Lvalue required' when I try to put a string in the array (starr[i]=s)?

And what should I use instead if this brings up an error?

Last edited by Sin-da-cat; Nov 20th, 2006 at 1:43 pm.

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Re: Is it possible to arange lines in a file alphabetically?

#10

Nov 20th, 2006

Dont use direct assignment operator. You can't treat strings like normal data types in terms of assignment.

You need to use strcpy to do somthing like that.