Splitting string into words. Symmetrical words. C language.

We are given a string. We need to split a string into words and find a symmetrical words.

#include <stdio.h>
#include <conio.h>
#include <string.h>
#include <alloc.h>
#include <ctype.h>


int main(int argc, char* argv[])
{
char* s;
int i=0, j, sim=0, l, k, n;
s = (char*)calloc(100, sizeof(char));
puts("Enter string:");
gets(s);

n = strlen(s);

while (i < n) {
        while ( (i < n) && (!isalpha(s[i])) ) i++;
        j = i;
        while ( (j < n) && (isalpha(s[j])) ) j++;

        l = 0;
        k = 0;
        while ( i + k < j - 1 - k  ) {
                if ( s[i+k] != s[j-1-k]) {
                        l = 1;
                        break;
                }
                k++;
        }
        if ( (i < n) && (l == 0) ) sim++;
        i = j;    
}
printf("sim = %d",sim);
free(s);
getch();

return 0;
}