c++ – I Want This Code To Prove If An Integer Is A Palindrome. How Do I do It?

I’m not sure what you’re trying to do in isPalindrome.
One way to check if a string of size len is palindrome is to compare its i-th and (len-i-1)-th characters for i ranging in [0, len / 2).
If they differ at any point the string is not palindrome.

Here’s how you may do it:

bool isPalindrome(std::string const& md) {
    if (md.empty()) // Empty strings are not palindrome
        return false;
    
    auto const len = md.size();
    auto const halfLen = len / 2;
    for (std::size_t i = 0; i != halfLen; ++i)
        if (md[i] != md[len - i - 1])
            return false;

    return true;
}

Can anyone help me, and if possible, without changing much of the code tell
me ways to achieve what I want to (to prove palindrome-ism)?

Please check the comments I’ve added in the code:

// Include the correct headers
#include <iostream>
#include <string>

// Don't do this
//using namespace std;

// This just checks if the string is palindrome.
// It does not print anything.
bool isPalindrome(std::string const& md) {
    if (md.empty())
        return false;
    
    auto const len = md.size();
    auto const halfLen = len / 2;
    for (std::size_t i = 0; i != halfLen; ++i)
        if (md[i] != md[len - i - 1])
            return false;

    return true;
}

int main() {
    // No need to parse the number and convert it to string again.
    //int x;

    std::string md;
    std::cout << "What is the integer you wanna check palindromism for?: ";
    // NOTE: you may input any string here: not just integers.
    std::cin >> md;

    std::cout << (isPalindrome(md) ? "YES" : "") << '\n';
//                                   ^ print "YES" or nothing

    return 0;
}

You may also implement isPalindrome with algorithms and iterators like so:

// You'll need these two headers
#include <algorithm>
#include <iterator>

template <typename BidIt>
bool isPalindrome(BidIt first, BidIt last) {
    if (first == last)
        return false;

    auto const halfLength = std::distance(first, last);
    auto const mid = std::next(first, halfLength);
    auto const rFirst = std::make_reverse_iterator(last);
    return std::equal(first, mid, rFirst);
}

bool isPalindrome(std::string const& str) {
    return isPalindrome(std::cbegin(str), std::cend(str));
}

This is basically the same algorithm as above but you can reuse

template <typename BidIt>
bool isPalindrome(BidIt, BidIt);

with more containers than just std::string.