package main

import "fmt"

func main() {
        for i := 10; i < 100; i++ {
                a, b := i/10, i%10
                if a+b*16 == i {
                        fmt.Printf("%d == 0x%d%d\n", i, b, a)
                }
        }
}

_>Не кошерно. Надо на C++20 с помощью метапрограммирования сделать

#include <string>
#include <sstream>
#include <map>
#include <vector>
#include <algorithm> // std::for_each
#include <memory>

using namespace std;

using MAP_IH = map<int, string>;
using INT_VECTOR = vector<int>;

class CHexCount
{
public:
    CHexCount();
    ~CHexCount();
    MAP_IH& GetMapIntHex();

    INT_VECTOR CalculateMagicNumbers();
private:
    MAP_IH m_mapIntHex;
};

CHexCount::CHexCount()
{    
    for (int i = 1; i < 128; i++)
    {
        stringstream ss;
        ss << std::hex << i;
        string sOut = ss.str();

        m_mapIntHex[i] = sOut;
    }
}
...
INT_VECTOR CHexCount::CalculateMagicNumbers()
{
    INT_VECTOR vectMagicNums;
    std::for_each(cbegin(m_mapIntHex), cend(m_mapIntHex), [&vectMagicNums](pair<int, string> pairIntHex)
    {
        stringstream ss;
        ss << pairIntHex.first;
        string strInt = ss.str();
        
        string strHex = pairIntHex.second;

        int iStrSize1 = strInt.size();
        int iStrSize2 = strHex.size();
        if ((iStrSize1 == 2) && (iStrSize2 == 2))
        {
            char chrInt0 = strInt[0];
            char chrInt1 = strInt[1];
            if ((strHex[0] == chrInt1) && (strHex[1] == chrInt0))
            {
                vectMagicNums.push_back(pairIntHex.first);
            }
        }
    });
    return vectMagicNums;
}

_>>Не кошерно. Надо на C++20 с помощью метапрограммирования сделать

template<int n> struct C { enum {
    ab=C<n-1>::ab+1,
    a=ab/10,
    b=ab%10,
    h=b*16+a,
    r=(ab==h)?ab:C<n-1>::r
};};
template<>struct C<0> { enum { r,ab=r }; };

#include<iostream>
int main(int argc,char** argv) {
    std::cout<<"age="<<C<99>::r<<std::endl;
    return 0;
}

#include <iostream>

void main()
{
   int year;
   std::cout << "Vvedite god vashego rozhdeniya: ";
   std::cin >> year;
   std::cout << 2018 - year;
}

AG>Сегодня у меня ДР

DECLARE @s bigint = 10
    ,   @e bigint = 100

;WITH 
Z AS (SELECT 0 z FROM (VALUES (0),(1),(2),(3),(4),(5),(6),(7),(8),(9),(10),(11),(12),(13),(14),(15)) T(n)),
Y AS (SELECT 0 z FROM Z a, Z b, Z c, Z d, Z e, Z f, Z g, Z h, Z i, Z j, Z k, Z l, Z m, Z n, Z o, Z p),
N AS (SELECT ROW_NUMBER() OVER (PARTITION BY 0 ORDER BY z) n FROM Y)

SELECT TOP 1 @s + n - 1 age FROM N /* ни в коем случае не ставить больше top 1 */
WHERE @s + n - 1 = (@s + n - 1) % 16 * 10 + (@s + n - 1) / 16

DL>DECLARE @s bigint = 10
DL>    ,   @e bigint = 100

DL>;WITH 
DL>Z AS (SELECT 0 z FROM (VALUES (0),(1),(2),(3),(4),(5),(6),(7),(8),(9),(10),(11),(12),(13),(14),(15)) T(n)),
DL>Y AS (SELECT 0 z FROM Z a, Z b, Z c, Z d, Z e, Z f, Z g, Z h, Z i, Z j, Z k, Z l, Z m, Z n, Z o, Z p),
DL>N AS (SELECT ROW_NUMBER() OVER (PARTITION BY 0 ORDER BY z) n FROM Y)

DL>SELECT TOP 1 @s + n - 1 age FROM N /* ни в коем случае не ставить больше top 1 */
DL>WHERE @s + n - 1 = (@s + n - 1) % 16 * 10 + (@s + n - 1) / 16
DL>

SELECT age FROM generate_series(10, 99) AS age WHERE age = age%16*10 + age/16;

10 1 0 1 1 FALSE
11 1 1 11 B FALSE
12 1 2 21 15 FALSE
13 1 3 31 1F FALSE
14 1 4 41 29 FALSE
15 1 5 51 33 FALSE
16 1 6 61 3D FALSE
17 1 7 71 47 FALSE
18 1 8 81 51 FALSE
19 1 9 91 5B FALSE
20 2 0 2 2 FALSE
21 2 1 12 C FALSE
22 2 2 22 16 FALSE
23 2 3 32 20 FALSE
24 2 4 42 2A FALSE
25 2 5 52 34 FALSE
26 2 6 62 3E FALSE
27 2 7 72 48 FALSE
28 2 8 82 52 FALSE
29 2 9 92 5C FALSE
30 3 0 3 3 FALSE
31 3 1 13 D FALSE
32 3 2 23 17 FALSE
33 3 3 33 21 FALSE
34 3 4 43 2B FALSE
35 3 5 53 35 TRUE