Определить строки этого файла, содержащие максимальную по длине подстроку, состоящую из одинаковых символов

#include <iostream>
#include <cstdio>
#include <cstring>
 
using namespace std;
 
const int MAXN = 1000;
 
int main() {
FILE* fin;
char *current_string = new char[MAXN + 1];
char* answers[10];
int max_len_in_file = 0, number_of_answers = 0;
 
if ((fin = fopen("input.txt", "r")) == NULL) {
cout << "File can't be opened" << endl;
return 0;
}
fgets(current_string, MAXN, fin);
if (feof(fin)) {
cout << "File is empty" << endl;
system("pause");
return 0;
}
 
// ????? ?????? ??????? ?? ?????, ???? ??? ?? ??????????
 
do {
// ??? ??? ? ??? ????????? ????? ???????
int length = strlen(current_string);
if (length == 0) {
fgets(current_string, MAXN, fin);
continue;
}
 
char* copy_of_string = new char[length + 1];
 
strcpy(copy_of_string, current_string);
// ???????? ? ??????? ????????
strlwr(copy_of_string);
 
int maxlen = 0;
for (int begin = 0; begin < length; ++begin) {
// ?? ????? - ?????????? ????? ??????
if (!isalpha(copy_of_string[begin])) continue;
 
for (int end = begin + 1; end < length; ++end)
if (copy_of_string[end] != copy_of_string[begin]) {
int newlen = end - begin;
if (newlen > maxlen) {
maxlen = newlen;
}
break;
}
}
 
if (maxlen > max_len_in_file) {
for (int i = 0; i < number_of_answers; ++i) delete [] answers[i];
 
number_of_answers = 1;
max_len_in_file = maxlen;
 
answers[0] = new char[length + 1];
strcpy(answers[0], current_string);
 
fgets(current_string, MAXN, fin);
delete [] copy_of_string;
continue;
}
 
if (maxlen == max_len_in_file && number_of_answers < 10) {
answers[number_of_answers] = new char[length + 1];
strcpy(answers[number_of_answers], current_string);
number_of_answers++;
}
 
delete [] copy_of_string;
fgets(current_string, MAXN, fin);
} while (!feof(fin));
delete [] current_string;
 
cout << "Max length = " << max_len_in_file << endl;
cout << "Number of answers = " << number_of_answers << endl;
 
for (int i = 0; i < number_of_answers; ++i) cout << answers[i];
system ("pause");
return 0;
}

 ifstream in;
        in.open("input.txt");
        ofstream  out;
        out.open("output.txt"); 
        in>>x>>y;

#include <fstream>