empty output on brute force task - c++

Question

I am working on a brute force task, but when I run my program, it gives an empty output file. Can anybody please help me fix this? The problem statement is below along with my code after that.
PROBLEM STATEMENT:
Write a program that reads two numbers (expressed in base 10):
N (1 <= N <= 15)
S (0 < S < 10000)
and then finds and prints (in base 10) the first N numbers strictly greater than S that are palindromic when written in two or more number bases (2 <= base <= 10).
Solutions to this problem do not require manipulating integers larger than the standard 32 bits.
CODE
#include <iostream>
#include <string>
#include <algorithm>
#include <vector>
#include <cmath>
#include <fstream>
using namespace std;
string convert(int num, int base)
{
int quo = 100000;
int rem = 0;
string to_reverse;
while (quo > 0)
{
quo = num / base;
rem = num % base;
to_reverse += to_string(rem);
num /= base;
}
reverse(to_reverse.begin(), to_reverse.end());
return to_reverse;
}
bool is_pal(string conv_num)
{
string reversed_conv_num = conv_num;
reverse(reversed_conv_num.begin(), reversed_conv_num.end());
if (reversed_conv_num == conv_num)
{
return true;
}
return false;
}
int main()
{
ofstream fout("dualpal.out");
ifstream fin("dualpal.in");
int n, start;
fin >> n >> start;
vector<int> finals;
int times = 0;
for (int i = start + 1; i <= 10000; i++)
{
if (times == n)
{
for (auto x : finals)
{
fout << x << "\n";
}
break;
}
else
{
for (int j = 2; j <= 10; j++)
{
if(is_pal(convert(i, j)) == true)
{
times++;
finals.push_back(i);
}
}
}
}
return 0;
}

Answer 1

Try this code. I made some changes.
#include <iostream>
#include <sstream>
#include <string>
#include <algorithm>
#include <vector>
#include <cmath>
#include <fstream>
using namespace std;
string convert(int num, int base)
{
int quo = 100000;
int rem = 0;
string to_reverse;
ostringstream str1; /*this and the next commented lines are added because "to_string" didnt work in my compiler*/
while (quo > 0)
{
quo = num / base;
rem = num % base;
str1 << rem; //this
to_reverse += str1.str(); //and this
num /= base;
}
reverse(to_reverse.begin(), to_reverse.end());
return to_reverse;
}
bool is_pal(string conv_num)
{
string reversed_conv_num = conv_num;
reverse(reversed_conv_num.begin(), reversed_conv_num.end());
if (reversed_conv_num == conv_num)
{
return true;
}
return false;
}
int main()
{
ofstream fout;
fout.open("dualpal.out", ios::out); //open the file in binary mode
//ifstream fin("dualpal.in");
int n, start;
cin >> n >> start;
vector<int> finals;
int times = 0;
for (int i = start + 1; i <= 10000; i++)
{
if (times == n)
{
//just a simple iterator for vector
for (vector<int>::iterator it = finals.begin(); it != finals.end(); ++it)
{
fout << *it << "\n";
}
break;
}
else
{
for (int j = 2; j <= 10; j++)
{
if(is_pal(convert(i, j)) == true)
{
times++;
finals.push_back(i);
}
}
}
}
fout.close(); //close the file
return 0;
}
USE OF STRING STREAMS
int number = 1000;
ostringstream s;
s << number;
string str = s.str();
This method can be used to convert number to strings.
This code requires <sstream> header file.