palindromes

[headball]

I need to write a program that opens a text file from the hard drive and find all the pa;indromes and all the non-palindromes and count the number of palindromes. How can i do this?

[Chris Eastwood]

This code will tell you whether the passed string is a palindrome :


private Function IsPalindrome(byval sString as string)
Dim sLeft as string
Dim sRight as string
'
sLeft = Left$(sString, len(sString) / 2)
sRight = Right$(sString, len(sString) / 2)
'
IsPalindrome = (StrComp(sLeft, StrReverse(sRight), vbTextCompare) = 0)
'
End Function




eg.


MsgBox IsPalinDrome("Edam I Made") ' returns true




- Requires VB6 for the 'StrReverse' function (but you can always rewrite that in VB5).


Chris Eastwood

CodeGuru - the website for developers
http://codeguru.developer.com/vb

[Cakkie]

Here's the vb5 version:

public sub command1_click()

dim fFile as integer
dim palindromes as integer
dim nonPalidromes as integer
fFile = freefile

open "palindromes.dat" for input as #ffile

do while not(eof(ffile))

line input #ffile, strLine
if IsPalindrome(strLine) then
palindromes = palindromes + 1
else
nonPalidromes = nonPalindromes + 1
end if

loop

close #ffile

end sub

public function IsPalindrome(strToCheck as string) as boolean

tmpWord = ""

for t=1 to len(strToCheck)
tmpWord = mid(strToCheck,t,1) & tmpWord
next t

if tmpWord = strToCheck then
IsPalindrome = true
else
IsPalindrome = false
end if

End Function




Tom Cannaerts
[email protected]

The best way to escape a problem, is to solve it.

[Chris Eastwood]

I'd recommend that you change the code :


If tmpWord = strToCheck then
IsPalindrome = true
else
IsPalindrome = false
End If



- to the method I used - the above doesn't take into account case sensitivity, eg "Edam I Made" would not be reported as a palindrome.

The StrComp command is very useful (and fast) for checking whether strings are equal regardless of case.

Chris Eastwood

CodeGuru - the website for developers
http://codeguru.developer.com/vb

[Cakkie]

...or you can just add 1 line in the function IsPalindrome. Place following line at the first line of the function:

strToCheck = LCase(strToCheck)
'this will place the string in lowercase, so when doing the check, the case will always match




Tom Cannaerts
[email protected]

The best way to escape a problem, is to solve it.