[chatterjee]

Dear fellows I've got stuck with a problem.

I want to write a program to check if a sequence of words is immediately repeated or not.

Suppose you entered a string-'bubble' ,it will be rejected because it has b and b subsequently.
similarly 'xyxy210' or 'abcabc154' will be rejected whereas 'abcbca154' will be accepted.

I thought over it again and again but found no result.

Any kind of help will be greatly appreciated.

Thanks in advance.

[AGCurry]

Hint: The solution to this problem is recursive.

The "end case" is where the length of the string <= 2.

[kidnewbie]

Originally Posted by chatterjee

Dear fellows I've got stuck with a problem.

I want to write a program to check if a sequence of words is immediately repeated or not.

Suppose you entered a string-'bubble' ,it will be rejected because it has b and b subsequently.
similarly 'xyxy210' or 'abcabc154' will be rejected whereas 'abcbca154' will be accepted.

I thought over it again and again but found no result.

Any kind of help will be greatly appreciated.

Thanks in advance.

'abcbca154' should also be rejected since 'bc' is repeated

i could have helped you if this question was asked 3 months ago. my programming is kinda rusty cause i haven't had any practice.

i'll still try look into it and post anything that might be helpful

but like AGCurry said, recursion is definitely the answer

[Jimmy the Hand]

I don't use C, but here's an algorhythm for you.

Given is a string, which is to be examined. Call it SStr. For example, SStr = "asehsehateafr"

1. Pick the 1st character in SStr. In this example, it will be "a".
2. Look for the next "a" in the string. In this example, it will be at character position 8.
3. Copy two substrings, one starting with the 1st "a" the other starting with the 2nd "a", and both of them 7 characters long (distance between the two "a"-s). May want to put the substrings into variables.
4. Compare the substrings. If they are the same, take appropriate action. If not, step forward in algorhythm.
5. Look for the next "a" in SStr. This, if found, will be the 3rd "a" in the string. Make substrings, compare them. Etc.
6. When there are no more "a"-s, or the distance between the first "a" and the currently found "a" is more than half of the string length, exit cycle.
7. Pick the 2nd character in SStr. In this example, it will be "s".
8. Process it as you did with "a"
9. Do the same with each character of SStr, until you reach the last one ("r").

[chatterjee]

Thank you all for giving your helping hand.

To tell the truth,I'm a C newbie coz I've learnt the language a month or two ago.And that's why I'm not that comfortable with recursion still now.

Malcka,I'll surely try your suggestion.But there is a problem...in BASIC I could have used the MID$ function to cut the string at the desired position but I don't know which function I should use to do the same in C.

BTW,thank you for your support.Please provide me with any ideas thant come come into your mind about solving this problem.

And lastly,I'm extremely sorry for giving you a wrong example.Rather,this should be the example'abcdcbad54'

[blaqDeaph]

Wouldnt it be easier to use for loops and strstr()? May be more elegant with recursion though.