Palindromic Squares

/*ID: america6PROG: palsquareLANG: C++11*/#include <iostream>#include <fstream>#include <string>using namespace std;string trans(int base, int num) {    string tn;    while (num) {        int d = num%base;        if (d >= 0 && d <= 9) {            tn.insert(tn.begin(), '0'+d);        }        else if (d >= 10) {            tn.insert(tn.begin(), 'A'+d-10);        }        num/=base;    }    return tn;}bool pal(string tn) {    int i = 0, j = tn.size()-1;    while (i < j) {        if (tn[i] != tn[j]) {            return false;        }        i++;        j--;    }    return true;}int main() {    ofstream fout ("palsquare.out");    ifstream fin ("palsquare.in");    int a;    fin >> a;    for (int i = 1; i <= 300; ++i) {        string s = trans(a, i*i);        if (pal(s)) {            fout << trans(a, i) << " " << s << endl;        }    }    return 0;}