reversehex.cpp

#include <iostream>
using namespace std;

int reverseAsHex(int n) {
  int mask = 0xF; // or 15
  int answer = 0;
  while (n != 0) {
    answer = (answer << 4) | (n & mask);
    n >>= 4;
  }
  return answer;
}

int main() {

  int num = 1234;
  cout << std::dec << num << endl;
  cout << std::hex << num << endl;

  int reverse = reverseAsHex(num);
  cout << std::dec << reverse << endl;
  cout << std::hex << reverse << endl;
}