Palindrome Detection

[AC_Drkan]

Code Select Expand


#include <stdio.h>
#include <string.h>
#define MAXLENGTH   100
#define TRUE         1
#define FALSE      0

int tester (char string1[MAXLENGTH])
{
   char string2[MAXLENGTH];
   char string3[MAXLENGTH];
   int i;
   
   for ( i = 0; i >= strlen(string1); ++i)
   {
      string3[ i ] = string1[ i ];
   }
   
   for ( i = strlen(string1); i <= 0; --i)
   {
      string2[ i ] = string1[ i ];
   }
   
   printf ("PASSED LOOP");
   
   if (string2 == string3)
   {
      return TRUE;
   }
   if (string2 != string3)
   {
      return FALSE;
   }
   else
   {
      printf ("Didn't understand the input. Exiting...\n");
   }
   
}

main ()
{
   char enter[MAXLENGTH];
   int result;

   printf ("Enter a Word: ");
   scanf("%s", enter);
   
   result = tester (enter);
   
   if ( result == TRUE )
      printf ("\nYES %s is a Palindrome\n", enter);
   else if ( result == FALSE)
      printf ("\nNO %s isn't a Palindrome\n", enter);
   else
      printf ("\nDidn't understand the input. Exiting......\n");
}



ok
this is ther code im using to find out if words entered to string 1 are a palindrome.
radar is a palindrome.
mom is a palindrome.

Basically a palindrome is a word that can be spelled backwards and forwards and still be the same word

Please help
this project is due this friday

[MyndFyre]

Cmon man, a palindrome test is done in basic CS classes.  Don't be a lamer.  

It's a for loop that compares the final index to the first index, incrementing the first index and decrementing the last index.  When they are within 2 of each other, you are done (the string is a palindrome), or if they are not and they don't match, you break out of the loop, and it is not a palindrome.

[Eli_1]

   if (string2 == string3)
  {
     return TRUE;
  }
  if (string2 != string3)
  {
     return FALSE;
  }

I'm a newbie to C++, but wouldn't that raise an error. I didn't think you could compare character arrays like that.

strcmp?

Cmon man, a palindrome test is done in basic CS classes.  Don't be a lamer.  

It's a for loop that compares the final index to the first index, incrementing the first index and decrementing the last index.  When they are within 2 of each other, you are done (the string is a palindrome), or if they are not and they don't match, you break out of the loop, and it is not a palindrome.

Aww Mynd, don't be mean. 90% of people start with lame things like

Code Select Expand

"Hello, World!\n"
This is just the next step in a chain of lame beginning projects. Gotta crawl before you can walk... Or something like that...

[Adron]

bool palindrome(const char *str, int len) { return len < 2 || *str == len[str] && palindrome(str + 1, len - 2) ; }


bool palindrome(const char *p) { for(char *q = p + strlen(p) - 1; q > p; q--, p++) if(*p != *q) return false; return true; }

[Arta]

eew @ doing people's homework

[iago]

eew @ doing people's homework

Of course, if you turn Adron's code into the majority of C++ classes you wouldn't get many marks anyway.

Based on the code you've given you have no idea what you're doing and should probably ask your teacher for help.  Seriously

[Eibro]

Much less efficient, but much clearer is

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bool palindrome( const string& in ) {
   string inrev = in;
   reverse( inrev.begin(), inrev.end() );
   return inrev == in;
}

[Mephisto]

ew @ calling main() without a return type!

[iago]

ew @ calling main() without a return type!

There are many technical and logical problems with his code, which is why I recommended he seek professional help.

[AC_Drkan]

ew @ calling main() without a return type!

There are many technical and logical problems with his code, which is why I recommended he seek professional help.

Me?

Cause it runs, but it just returns no for everything i do
and
strcmp(string1,"hi")
would return 0 if string1 is exactly equal to hi

If you want an example here ya go:

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if (stricmp(szSpeaker,"angel_drkan@azeroth") == 0)
{
   Send("/emote . : Greetings Master, Users logged on since my log on: %i, Currently on Number %i : .\r\n", y, x);
   x = x - 1;
   return 1;
}

I use that in my greet bots.

[Adron]

eew @ doing people's homework

I was thinking about whether to post commented pseudo-code/ideas or uncommented c++ code. I chose this because it was more fun. I figure he'll have to understand his answer to be able to get a score for it anyway. This way he'll get to ponder two solutions - which one to pick...