How do you check given string is palindrome or not with out using string functions?

Answer 1

/*To check whether a string is palindrome*/

1. include
2. include

void main () {
int i,j,f=0;
char a[10];
clrscr ();
gets(a);
for (i=0;a[i]!='\0';i++)
{
}
i--;
for (j=0;a[j]!='\0';j++,i--)
{
if (a[i]!=a[j])
f=1;
}
if (f==0)
printf("string is palindrome");
else printf("string is not palindrome");
getch ();
}

Answer 2

If you mean not using pointers, then:

int palindrome (const char s[])

{

size_t len, i, j;

len = strlen (s);

for (i=0, j=len-1, check=1; check==1 && i

if (s[i] != s[j]) check= 0;

}

return check;

}

but if it's using pointers, then: int palindrome (const char *s)

{

size_t len;

const char *p, *q;

len = strlen (s);

for (p=s, q=s+len-1, check=1; check==1 && p

if (*p != *q) check= 0;

}

return check;

}

Answer 3

int palindrome(char * string)

{

int result = 0;

int count = 0;

char * a = string;

char * b = string+strlen(string);

while((*a++ strlen(string))

result = 1;

return result;

}

Answer 4

#include

#include

#include

void main()

{

clrscr();

int i,j=0;

char s[40]=" ";

int p = 1;

printf("/nEnter the string;");

gets(s);

for(i=strlen(s)-1;i>=0;i--,j++)

{

if (s[j] !=s[i])

{

p=0;

break;

}

}

if(p)

printf("Given string %s is palindrome",s);

else

printf("Given string %s is not palindrome",s);

getch();

}

strlen is one of the string functions

Answer 5

#include<stdio.h>

#include<ctype.h>

#include<string.h>

/* returns true of the given string represents a palindrome,

otherwise returns false */

bool is_palindrome (const char* str) {

size_t len;

char *left, *right;

if (!str) return false; /* null-strings are not palindromes */

len = strlen (str);

if (!len) return false; /* empty strings are not palindromes */

left = (char*) str;

right = (char*) str + len - 1;

while (left<right && *left==*right) {

++left;

--right;

}

return (*left==*right);

}

int main (void) {

char str[BUFSIZ], cpy[BUFSIZ];

size_t i, index;

printf("Enter a string: ");

gets(str);

/* strip punctuation and convert to lower case */

i=0;

for (index=0;index<BUFSIZ;++index) {

cpy[i]=tolower(str[index]);

if (cpy[i]>='a' && cpy[i]<='z')

++i;

}

cpy[i]='\0';

/* print result */

printf ("The string "%s" is ", str);

if (!is_palindrome (cpy))

printf ("not ");

printf ("a palindrome.\n");

}

Example usage:

Enter a string: Madam, I'm Adam

The string "Madam, I'm Adam" is a palindrome.

Enter a string: Madam, I'm not Adam

The string "Madam, I'm not Adam" is not a palindrome.