i am also seeing the similar problem.. the code is here..

#include<stdio.h>
#include<string.h>
int palindrome(char *a,int n);
int main()
{
char a[20];
int b,n;
printf("Enter the string to be checked\n");
scanf("%s",a);
printf("The entered string is ");
puts(a);
printf("%c%c%c",a[0],a[1],a[2]);
//empty line
strlen(a);
b=palindrome(a,n);
if(b==0)
printf("%s is palindrome\n",a);
else
printf("%s is not palindrome\n",a);
}
int palindrome(char *a,int n)
{
int i=0;
int j=n-1;
for(;i<j;i++,j--)
{
//no empty line
//printf("%d",i);
printf("%c",a[i]);
printf("%c",a[j]);
//printf("%d",strcmp(a[i],a[j]));
if(a[i]!=a[j])
return(0);
}
return(1);
}

i wrote similar code in other format...

#include<stdio.h>
#include<string.h>
int palindrome(char *a, int n);
int main()
{
char a[20];
//char b[20];
int c,n;
printf("Enter the string to check");
scanf("%s",a);
//scanf("%s",b);
//printf("The entered string is ");
puts(a);
//puts(b);
n=strlen(a);
c=palindrome(a,n);
if(c==0)
printf("The string is palindrome");
else
printf("The string is not palindrome");
}
int palindrome(char *a, int n)
{
int i=0,j=n-1;
for(;i<j;i++,j--)
//{
//printf("%c  ",a[i]);
//printf("%c",a[j]);
if(a[i]!=a[j])
return(1);
//}
return(0);
}

The second one is working.. the first one returns error of segmentation fault core dump.

I am using cygwin gcc recent version for compilation. The error file is generated for first code upon executing with extn of .stackdump.

The error file is

Exception: STATUS_ACCESS_VIOLATION at eip=00401144
eax=49662080 ebx=61227A1E ecx=6115B320 edx=00000000 esi=61227A2D edi=00000000
ebp=0022CCF8 esp=0022CCE0 program=C:\cygwin\home\LP-0126\palindrome.exe, pid 3536, thread main
cs=001B ds=0023 es=0023 fs=003B gs=0000 ss=0023
Stack trace:
Frame Function Args
0022CCF8 00401144 (0022CD40, 49435341, 00000065, 0000006E)
0022CD68 004010D6 (00000001, 61227AA4, 006700F8, 610049BE)
0022CD98 61006E73 (00000000, 0022CDD4, 61006720, 7FFD5000)
End of stack trace

Nice elegant function for 'palindrome'.
Your string buffer is completely unprotected.
Writing safe string code in C isn't too hard, but you have to change most of your function calls. First, if you allocate fixed arrays, 'sizeof' is your friend.

// use a reasonable buffer-size.  RAM is cheap.  Any single variable can go to 4096 without thinking.
#define BUFFERSIZE 250
	assert( BUFFERSIZE > 1 );
	char a[BUFFERSIZE];
	size_t last= sizeof(a)-1; // with a fixed array this always gets last byte

The scanf function is dangerous. One way to protect your buffer is to provide a length limiter in the "%s" string format, as in "%20s". Here is some code to do that:
Also, always terminate a string buffer after input, because some functions don't do it for you.

char fmt[100]; // enough to hold any number
	sprintf_s(fmt,sizeof(fmt),"%%%ds",last); // an array of size 10 will yield "%9s".
// always terminate a string returned from a function
	fmt[ sizeof(fmt)-1 ] =0; 
	printf("generated format string: \"%s\"\n",fmt);

Now you have a format string that guarantees 'scanf' won't clobber your buffer.

scanf(fmt,a); // get user input
         // now, to get the length of user-generated input.
         // strlen, right?  not so fast..
         // size_t n= strlen(a); // no! very dangerous. 'a' could be unterminated
	a[last]=0; // force-terminate the string.  It's cheap and easy.
         size_t n= strlen(a); // okay now, because string will never overrun.
	printf("input: \"%s\"\n",a);
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