PAT 1040 Longest Symmetric String

#include <cstdio>
#include <cstdlib>

using namespace std;

char line[];
char line2[];

int syslen(char str[], int start) {
    int len = ;
    int p = start - ;
    int q = start + ;
    while (p >= && str[q] != '\0' && str[p] == str[q]) {
        p--, q++;
        len += ;
    }
    return len;
}

int main() {
    scanf("%[^\n]s", line);

    int p = , q = ;
    line2[p++] = ' ';
    line2[p++] = line[q++];
    while (line[q] != '\0') {
        line2[p++] = ' '; // dummy char used as seperator
        line2[p++] = line[q++];
    }
    line2[p++] = ' ';
    line2[p] = '\0';
    int max_len = ;
    for (int i=; i<p; i++) {
        int cur_len = syslen(line2, i);
        if (cur_len > max_len) max_len = cur_len;
    }
    printf("%d", max_len/);
    return ;
}

brute force for small case