palindrome

Can anyone please advise wad's wrong with this code...why do i still get 0 despite typing in radar...

Code:

 1 #include <stdio.h>
  2 #include <string.h>
  3     
  4 int isPalindrome1(const char *str);
  5          
  6 int main ( ) 
  7 {
  8     char str [40];
  9     int result;
 10     scanf("%s",str);
 11 
 12     result=isPalindrome1(&str);
 13     printf("%d",result); 
 14 
 15     return 0;
 16 }
 17 
 18 int isPalindrome1 (const char *str)
 19 {
 20     char temp1 [40];
 21     char temp2 [40];
 22     int i=0;
 23     int length=0;
 24     int result=0;
 25 
 26     strcpy (temp1,str);
 27     length=strlen(temp1);
 28     for (i=0; i<length; i++)
 29         temp2[i]=temp1[length-i];
 30 
 31     if(strcmp(temp2,str)=='\0')
 32         result=1;
 33     else
 34         result=0;
 35 
 36     return result;
 37 }

o...i got it

Code:

  1 #include <stdio.h>
  2 #include <string.h>
  3 
  4 int isPalindrome1(const char *str); 
  5   
  6 int main ( )
  7 {
  8     char str [40];
  9     int result;
 10     scanf("%s",str);
 11 
 12     result=isPalindrome1(&str);
 13     printf("%d",result); 
 14 
 15     return 0;
 16 }
 17 
 18 int isPalindrome1 (const char *str)
 19 {
 20     char temp1 [40];
 21     char temp2 [40];
 22     int i=0;
 23     int length=0;
 24     int result=0;
 25 
 26    strcpy (temp1,str);
 27     length=strlen(temp1);
 28     for (i=0; i<=length; i++)
 29         temp2[i]=temp1[length-i-1];
 30     if(strcmp(temp2,str)=='\0')
 31         result=1;
 32     else
 33         result=0;
 34 
 35     return result;

Very good, but there is a faster and easier way...

Basically you compare the ends, moving in and exiting on the first difference...

Code:

int IsPalindrome(char *str)
  { int i = 0;
     int j = strlen(str) -1;

     while (j > i)
       { if ( str[i] != str[j])
           return 0;  // no it isn't
         i++;
         j--; }
    
     return 1; }      // yes it is!

Thanks, m trying a anagram code oso...can u pls advise why this code isnt working....it's printing 0 even for anagrams....

Code:

 1 #include <stdio.h>
  2 #include <string.h>
  3 
  4 int isAnagram1(char *str1, char *str2);
  5 int isAnagram2(const char *str1, char *str2);
  6 int isAnagram3(const char *str1, const char *str2);
  7 void sort (char *str, int length);
  8 void swap (char *a, char*b);
  9 
 10 int main ( )
 11 {
 12     int result=0;
 13     //int check=0;
 14     //int triplecheck=0;
 15     char str1 [50];
 16     char str2 [50];
 17 
 18     scanf("%s %s", str1, str2);
 19 
 20     result=isAnagram1(&str1, &str2);
 21     //check=isAnagram2(&str1, &str2);
 22     //triplecheck=isAnagram3 (&str1, &str2);
 23 
 24     printf("%d\n", result);
 25     //printf("%d\n", check);
 26     //printf("%d\n", triplecheck);
 27 
 28     return 0;
 29 }
 30 
 31 int isAnagram1(char *str1, char *str2)
 32 {
 33     int length1=0;
 34     int length2=0;
 35     int result=0;
 36 
 37     length1=strlen(str1);
 38     length2=strlen(str2); 
 39     sort(&str1, length1); 
 40     sort(&str2, length2); 
 41      
 42     if (strcmp(str1,str2)=='\0')
 43         result=1; 
 44     else 
 45         result=0; 
 46  
 47     return result; 
 48 } 
 49  
 50 void sort (char *str, int length)
 51 { 
 52     int i=0;int j=0; 
 53      
 54     for (j=0; j<length; j++)
 55     for (i=j+1;i<length; i++)
 56         if (str[j]>str[i])
 57             swap( &str[i],&str[j]);
 58  } 
 59  
 60 void swap (char *a, char*b)
 61 { 
 62     char temp; 
 63     temp=a; 
 64     a=b; 
 65     b=temp;

there's a } on line 66

You could do us all a favour by not posting code with the line numbers included. The board adds it's own line numbers anyway - if you do it properly.

Also, your swap function should be generating warnings - try fixing them.

sorry...m not sure how to remove the line numbers...i'll take note...

and i'm unsure how to fix the swap function....do i put a * in front of temp?

changed the swap function to this....but...now when i execute the programme...i get segmentation fault(core dumped)

Code:

 void swap (char *a, char*b)
 {
    char temp;
    temp=*a;
    *a=*b; 
    *b=temp;
 }

39 sort(&str1, length1);
40 sort(&str2, length2);
What about the warnings on these lines as well?

hmmm....i know there are warnings on lines 20, 39 and 40 oso...but i reali dunno how to fix them....isnt the function sort expecting a string? so wads wrong when i send in the address?

pls advise. tks a million

o...the programme runs fine when i remove both the & ....but why? i thot when i see * ...i must put & in the function call???

Here's what to do.

1. compile your code
2. fix ALL the warnings and errors.
3. if you don't understand a specific error message, then post your code and exact error messages.

Because all this "well some stuff happens" and general guessing doesn't work.

Hi...i wrote another version for anagrams...but i dun understand why does it always return 0...no warnings or errors in the function....can u help me to decipher the code the tell me what's wrong...thanks..

Code:

 int isAnagram3(const char *str1, const char *str2)
 {
     char num = 'a';
     int i=0;
     int j=0;
     int count1=0;
     int count2=0;
     int length1=0;
     int length2=0;
     int result=1;
 
     length1=strlen(str1);
     length2=strlen(str2);
     for (num='a'; num<='z'; num++)
     {
         for (i=0;i<length1;i++)
             if (str1[i]==num)
                 count1++;
         for (j=0; j<length2; j++)
             if (str2[j]==num)
                 count2++;
 
         if (count1!=count2)
         {
             result=0;break;
         }
     }
     return result;
 }

not sure why count1=1; count2=0....den they are not equals.....if they are anagrams, why is count1 !=count2?

added this on line 117....but no difference....count1=0;count2=0;