i need to find a substring in a string and get the next 3 characters

anurupr · 03-05-2010, 03:00 PM

for example

010100
this is the string

the substring is 010

i need to search for this substring and i also need to return the next 3 characters i.e 100.

i need to apply this for this string

01010000001001100000100010

is this possible somehow ?

TB0ne · 03-05-2010, 03:11 PM

Quote:

Originally Posted by anurupr

for example

010100
this is the string

the substring is 010

i need to search for this substring and i also need to return the next 3 characters i.e 100.

i need to apply this for this string

01010000001001100000100010
is this possible somehow ?

Yes it is, very possible. Read the man pages on grep and awk, and some basic shell-scripting tutorials.

anurupr · 03-05-2010, 03:16 PM

oh ok... ill check that out .. is it possible in c++ ?

Tinkster · 03-05-2010, 03:38 PM

Certainly

TB0ne · 03-05-2010, 04:23 PM

Quote:

Originally Posted by anurupr

oh ok... ill check that out .. is it possible in c++ ?

Yes, and in pretty much any other programming language too.

grail · 03-06-2010, 02:11 AM

You may also need to consider all your output options here too:

eg. your first string '010100' contains the characters 010 twice.

Also, what if you encounter 010 but there are not 3 characters after (ie 01011).
Do you retrun just the 2 characters, do you pad the last character (if so, with what)
or do you simply ignore this scenario as invalid as not 3 characters.

Just a thought

btw. these considerations are irrelevant of language or program used

anurupr · 03-07-2010, 12:52 AM

@grail i considered that .. the string that im going to input into this program is going to be of a proper form

dsmyth · 03-07-2010, 05:41 PM

Hi, most languages (and I'm thinking Ruby and Python) have a String class that contains methods that let you search for substrings. The result of these methods is usually the index (the position) of the first character within the string. Using this position + the length of the searched substring you can find the start position of the following 3 characters.

the string "supercalifragilisticexpialidocious"
is just a list or characters in an array

Code:

supercalifragilisticexpialidocious
0123456789012345678901235456789012
          111111111122222222222333

so a search for 'frag' using these methods will return 9, the position of 'f'. 'frag' is 4 characters long so add 4 to 9 and you get 13 (the i character).

I'm not sure if C++ has a String class but I'm fairly confident that there will be methods that will find the position of a substring within a longer string; no idea what they are though.

Hope this was a little bit helpful.

devnull10 · 03-07-2010, 05:45 PM

Code:

man string

use strstr to locate the substring

Code:

man strstr