palindrome function

This is a discussion on palindrome function within the C++ Programming forums, part of the General Programming Boards category; ok here is how i figure i would do it... get input determine lenght of string and reverse it bu ...

  1. #1
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    palindrome function

    ok here is how i figure i would do it...

    get input
    determine lenght of string and reverse it bu looping a decreasing for loop and concatenating the strings into a second string
    eg: text[100] added to reversedstring then text[99] added to reverstring and so on...

    then i would use the strcmp function to test for equality and see if it is indeed a palindrome... is this the best way to do it? anyone else have some faster or better pseusocode also i dont know how to determine the lenght of a string

  2. #2
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    use strlen(string) for length
    strcmp(str1,str2) for cmp

    yeah its fast but more mem will be used

    or you could use 2 loops one from 0 and incrementing and the other one from 99 and decrementing; comparing 0-99, 1-98 so on to see for palindrome.

  3. #3
    Code Goddess Prelude's Avatar
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    This has been handled many times before, just click on this to see.

    -Prelude
    My best code is written with the delete key.

  4. #4
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    ok no i have a litle problem the uncommented lines i do not understand... what does tolower do?

    Code:
    char* start = text; //pass the whole array into the start variable
       char* end = text + strlen(text) - 1; //pass the last charecter of the array into end
       while(end > start)
       {
           if(tolower(*start) != tolower(*end))
           {
               return(0);
           }
           end--;
           start++;
       }
       return(1);

  5. #5
    Code Goddess Prelude's Avatar
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    tolower will return the upper case equivalent of the character that you pass to it.

    -Prelude
    My best code is written with the delete key.

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