反转字符串

void reverse(char s[], int l, int r) {
    for ( ; l < r; l++, r--) {
        s[l] = s[l] ^ s[r];
        s[r] = s[l] ^ s[r];
        s[l] = s[l] ^ s[r];
    }
}

void reverseString(char* s, int n) {
    reverse(s, 0, n - 1);
}