jwirth779
asked on
External Sorting
I need a simple (im sure its simple for you guys) algorithm that can sort a large textfile.
i need my program to first sort and then merge (nothing new!!) . the sorting stage would split my large textfile into several smaller sorted textfiles and and the merging stage would merge all these textfiles together to make the final sorted textfile. i have tried it myself but i cannot figure out the algorithm ( i always get stuck at some point and realise i cannot continue).
i dont want to have to use pointers...maybe there is some recursive method ??(not sure). i have looked at swag but there doesnt seem to be anything close enough to what i need.
Any help is more than appreciated !!! :)
Thanks a real lot!
i need my program to first sort and then merge (nothing new!!) . the sorting stage would split my large textfile into several smaller sorted textfiles and and the merging stage would merge all these textfiles together to make the final sorted textfile. i have tried it myself but i cannot figure out the algorithm ( i always get stuck at some point and realise i cannot continue).
i dont want to have to use pointers...maybe there is some recursive method ??(not sure). i have looked at swag but there doesnt seem to be anything close enough to what i need.
Any help is more than appreciated !!! :)
Thanks a real lot!
how do you want them sorted, I mean you could sort by alphabetical, length of line, numerical?
ASKER
numerical....ascending order preferably!!!
Homework per chance?
mlmcc
mlmcc
ASKER
no... why do you ask? im gonna increase the points...
i have a program which will sort 20000 numbers (but very fast) in ascending order!! Would you like to apadpt it (my sorting program) for you to make the numbers as an input from your textfile?
ASKER
yes that would be really good of you. but the thing is that i must use the sort and merge procedure that i described before (it is a technique so ill be able to sort even if i dont have enough memory - but im sure you know that already) Does your program use a sort and merge algorithm?
Thanks again for all you help!!! :)
Thanks again for all you help!!! :)
no it does not use merge. Do you want it without the merge algorithm (it is still very effecient - it picks up 20000 random numbers and then sorts them in an average speed of less that 4.5 seconds, i think that would be effecient enough!)
ASKER
the thing is that i really need a sort and merge algorithm so ill be able to sort a textfile no matter what the size of the textfile is....
this is an exmple of my textfile :
test 01 26 test
test 02 15 test
test 03 66 test
test 04 37 test
test 05 61 test
test 06 33 test
test 07 95 test
test 08 99 test
test 09 31 test
test 10 82 test
. . . .
. . . .
. . . .
test 500 34 test
there are 500 hundred lines.... and the second colomn of numbers are between 1-100 (colomn to be sorted!!).
preferably this textfile is split up in 10 smaller sorted files and then merged to form one large sorted file!!
any idea????
thanks guys!!
this is an exmple of my textfile :
test 01 26 test
test 02 15 test
test 03 66 test
test 04 37 test
test 05 61 test
test 06 33 test
test 07 95 test
test 08 99 test
test 09 31 test
test 10 82 test
. . . .
. . . .
. . . .
test 500 34 test
there are 500 hundred lines.... and the second colomn of numbers are between 1-100 (colomn to be sorted!!).
preferably this textfile is split up in 10 smaller sorted files and then merged to form one large sorted file!!
any idea????
thanks guys!!
i made a program which splits an unsorted textfile in 10 other textfiles. Sort the textfile and then create a new sorted textile!
SAMPLE INPUT IN UNSORTED TEXTFILE:
1 12
2 14
3 19
4 89
5 27
6 20
7 73
8 10
9 46
10 28
11 32
12 44
13 59
14 69
15 77
16 80
17 93
18 100
19 26
20 38
SAMPLE OUTPUT IN SORTED TEXTFILE
10
12
14
19
20
26
27
28
32
38
44
46
59
69
73
77
80
89
93
100
This is what you wanted or something similar!!! Hope i've of help. I you want it just tell me! :)
SAMPLE INPUT IN UNSORTED TEXTFILE:
1 12
2 14
3 19
4 89
5 27
6 20
7 73
8 10
9 46
10 28
11 32
12 44
13 59
14 69
15 77
16 80
17 93
18 100
19 26
20 38
SAMPLE OUTPUT IN SORTED TEXTFILE
10
12
14
19
20
26
27
28
32
38
44
46
59
69
73
77
80
89
93
100
This is what you wanted or something similar!!! Hope i've of help. I you want it just tell me! :)
ASKER
yeah that sounds great!! do you think you could pass it on to me???
it is a little bit long! do you have an email so i can send it to? Otherwise i write it for you
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ASKER
it looks real good...thx alot....im gonna go over it and then give you the points.... cheers mate.
no problem man!!!!!
Did it work!!
ASKER
yeah it works ok
im just having abit of a problem adapting it to for example 500 records... its more than good enough though...thanks alot!!!
i might have a couple of problems still.... if you want ill give you the points anyway!!
im just having abit of a problem adapting it to for example 500 records... its more than good enough though...thanks alot!!!
i might have a couple of problems still.... if you want ill give you the points anyway!!
I appreciate it very much. :)
ASKER
im having a problem to modify it to 1000 records for example....how come?
ASKER
ok sorted!! cheers...
all yours!
all yours!
Thank you very much, and by the way if you need anymore help, as long as i know i will help you